Little Conformal Symmetry by Rachel Houtz
Room: 202 Physics Bldg.
Host: Prof. Jay Hubisz / Contact: Yudaisy Salomón Sargentón, 315-443-5960
Given the lack of conventional SUSY signals in the LHC data, a more complicated story may be required to explain weak scale physics. I will present a new class of natural models which ensure the one-loop divergences in the Higgs mass are cancelled. The top-partners that cancel the top loop are new gauge bosons, and the symmetry relation that ensures the cancellation arises at an infrared fixed point. Such a cancellation mechanism can, a la Little Higgs models, push the scale of the new physics that completely solves the hierarchy problem up to 5-10 TeV. When embedded in a supersymmetric model, the stop and gaugino masses provide the cutoffs for the loops, and the mechanism ensures a cancellation between the stop and gaugino mass dependence of the Higgs mass parameter.
Information, Computation, and Thermodynamics in Cells - by Pankaj Mehta
Rooms 202/204
Host: Lisa Manning | Contact: Tyler Engstrom, taengstr@syr.edu
Cells live in complex and dynamic environments. Adapting to changing environments often requires cells to perform complex information processing, and cells have developed elaborate signaling networks to accomplish this feat. These biochemical networks are ubiquitous in biology. They range from naturally occurring biochemical networks in bacteria and higher organisms, to sophisticated synthetic cellular circuits that rewire cells to perform complex computations in response to specific inputs. The tremendous advances in our ability to understand and manipulate cellular information processing networks raise fundamental questions about the physics of information processing in living systems. I will discuss recent work in this direction trying to understand the fundamental constraints placed by (nonequilibrium) thermodynamics on the ability of cellular circuits to process information and perform computations and discuss the implications of our results for the emerging field of synthetic biology.
The wool over our eyes: how scientists think they and their institutions are objective, but aren’t by Brian Nord
Room: 202 Physics Bldg.
Morphogenesis of the first branchial arch - by Sevan Hopyan
Rooms 202/204
Host: Cristina Marchetti | Contact: Tyler Engstrom, taengstr@syr.edu
The nuanced shapes of emerging organ primordia are intimately related to pattern formation and postnatal function, although the mechanisms that shape a volume of tissue in the embryo are not well understood. The mandibular portion of the first branchial arch is composed of a volume of mesenchyme surrounded by a single cell layer epithelium. Here we ask how this structure acquires a proximally narrow and distally bulbous shape during outgrowth. Using the mouse embryo as a model system, we measured cell cycle times, as well as Young’s modulus and viscosity using atomic force microscopy. Incorporating these data into a finite element model, we show that the spatial variation of cell division and physical properties is insufficient to explain mandibular arch shape. By combining time lapse light sheet microscopy of intact mouse embryos with custom cell tracking, we observed that volumetric convergent extension due to the intercalation of mesenchymal cells in 3D likely underlies the narrow and elongate shape of the mandiublar arch mid-portion. By knocking-in a transgenic FRET-based vinculin tension sensor into the mouse genome, we show that relatively high amplitude cortical force oscillations correlate with mesenchymal cell intercalations, and are oriented by polarised actomyosin. Evidence from loss and gain of function studies suggest that Wnt5a acts as a directional cue to regulate both the orientation and oscillation amplitude of cell cortices.
Our Warped Universe: Strong Lensing and Deep Machine Learning in Modern Cosmology Surveys by Brian Nord
202 Physics Bldg.
Refreshments at 3:30 pm and the talk starting at 3:45 pm
Host: Prof. Scott Watson / Contact: Yudaisy Salomón Sargentón, 315-443-5960
Current and future galaxy surveys will provide data sets unprecedented in size and precision with which to measure dark energy, dark matter and the early universe through probes like strong gravitational lensing. I will discuss our progress in the Dark Energy Survey (DES) to detect, spectroscopically confirm, and characterize lenses. Then, we’ll look at the oncoming era of astronomically big data. Specifically, we’ll discuss techniques, results, and the potential of deep machine learning in its application to cosmology.
Early universe cosmology as a probe of fundamental physics by Ogan Ozsoy
Room: 202 Physics Bldg.
Advisor: Prof. Scott Watson / Contact: Yudaisy Salomón Sargentón, 315-443-5960
The features of the universe we probe today are a reflection of the underlying physics at high energies and is a powerful motivation that drives theoretical research in modern cosmology. Precision observations of the Cosmic Microwave Background Radiation and the Large Scale Structure in the universe have already taught us a great deal about what may have occurred at high energies and early times in the universe’s history. In particular, the inflationary paradigm and the existence of cold dark matter stands as the two main pillars of standard model of cosmology (LCDM) which constitutes much of our modern understanding of the world we see today from a cosmological perspective. Despite the successful reconciliation of these theoretical ideas with precision data, we are far from a complete understanding of the particle physics nature of dark matter, inflationary dynamics and how the post-inflationary evolution proceeds. In this talk, I will present several theoretical ideas motivated by bottom-up and top-down constructions in field theory and explore their observational consequences in the hope of shedding some light on these phenomena.
Defects and Rearrangements in Disordered Solids by Sven Wijtmans
Room: 202 Physics Bldg.
Advisor: Prof. Lisa Manning / Contact: Yudaisy Salomón Sargentón, 315-443-5960
In this thesis, I will investigate the properties of disordered materials under strain. Disordered materials encompass a large variety of materials, including glasses, polymers, and gels. There is currently no constitutive equation that describes these materials. Given the prevalence and usefulness of these materials, we derive tools to aid our understand of them. We develop a new method to isolate localized defects from extended vibrational modes in disordered solids. This method augments particle interactions with an artificial potential that acts as a high-pass filter: it preserves small-scale structures while pushing extended vibrational modes to higher frequencies. The low-frequency modes that remain are ``bare" defects; they are exponentially localized without the quadrupolar tails associated with elastic interactions. We demonstrate that these localized excitations are excellent predictors of plastic rearrangements in the solid. We characterize several of the properties of these defects that appear in mesoscopic theory of plasticity, including their distribution of energy barriers, number density, and size, which is a first step in testing and revising continuum models for plasticity in disordered solids. We study rearrangement types in disordered packings of particles with a harmonic potential at a range of packing fractions above jamming. We develop a generalizable procedure that classifies events by stress drop, energy drop, and reversibility under two protocols. We find a large population of contact change events that have no associated stress drop. Reversible events become more common at high pressures above a packing fraction of $\phi=0.865$, at which point line reversible events are more common than loop reversible events. At low pressures, irreversible events are associated with spatially extended events, while at high pressures reversible events are much more spatially localized.
TBD by Prateek Agrawal
202 Physics Bldg.
Host: Prof. Jay Hubisz / Contact: Yudaisy Salomón Sargentón, 315-443-5960
Geometry of twisted filaments - by Arshad Kudrolli
Rooms 202/204
Host: Joseph Paulsen | Contact: Tyler Engstrom, taengstr@syr.edu
We will discuss the fundamental interplay of geometry, elasticity, and
applied stress in determining the hierarchical shapes and mechanical
response of slender elastic materials. A ribbon under a subtle
combination of tension and twist can transform into a rich variety of
shapes including helicoids, triangular folds, tubes, plectonemes,
scrolls, and self-wrapped disordered crumpled structures. The
nucleation topological defects and the growth of wrinkles will be
analyzed with a far-far-threshold approach. We will then examine the
interaction between a set of uniform fibers which are twisted starting
from a hexagonal lattice arrangement. The non-Euclidean geometry of
twisted fiber bundles are an important motif in materials ranging from
cables to textiles and tissues. The evolution of defects as a function
of twist will be examined in light of a new model of the fiber bundle
structure.
Reviving Creativity in Our Introductory Physics Labs by Mats Selen
202 Physics Bldg.
Refreshments at 3:30 pm and the talk starting at 3:45 pm
Host: Prof. Gianfranco Vidali / Contact: Yudaisy Salomón Sargentón, 315-443-5960
Approaching a question without fear; coming up with an idea; designing an experiment; understanding assumptions; interpreting data and revising the idea (or the question) accordingly. Many physicists would claim they do this for a living, and most would be delighted to observe this behavior in their students, yet for a variety of reasons this is often not what we encourage in our introductory physics labs. We have developed a portable wireless lab system with the goal of putting simple yet powerful tools in the hands of every student, and we are currently piloting a new design-based approach to our introductory physics labs based on this tool. Our students invent experiments and acquire data, both in and out of the classroom, and share their data with each other and with instructors using an integrated cloud based repository. This new approach is allowing us to shift the focus of our introductory labs toward creativity, design, sense-making, and communication. I will describe this project and present some encouraging first results.
The Turbulent Vacuum by A.P. Balachandran
208 Physics Bldg.
Host: Prof. Simon Catterall / Contact: Yudaisy Salomón Sargentón, 315-443-5960
*The following work is jointly done with M.Asorey, F.Lizzi and G.Marmo. The vacuum state in relativistic quantum field theory is often pictured as devoid of striking properties, as vacuous. But instead the following are true : 1) Atoms or measuring apparatus inserted at space-like distances in vacuum should exhibit no correlations in the above image of the vacuum. But instead if they have localised states with orthogonal wave functions, and atom 1 is in ground state and 2 in an excited state at a space-like distance, either 1 will *never *be affected by 2 via photon emission (which is absurd) or it will be *instantaneously* affected violating causality. 2) Fields in a finite region, no matter how small, acting on the vacuum can produce *any* state in the Hilbert space. 3) Invariance of the vacuum is invariance of the world. (Coleman). 4)There are * no *localised detectors ! ( Implications for a causal quantum information theory ?) After discussions of the above, we apply them to the Rindler wedge. There we show that photon or graviton *cannot* be confined to the wedge : there is information leakage out of the wedge (but no unitarity violation). This happens because in qed and gravity , infrared effects break ( asymptotic ) Lorentz invariance . The above result has potential applications to black hole information paradox. The super selection rules in the two cases are charge and momentum conservation respectively.
The geometry and topology of granular matter - by Daniel Sussman
Rooms 202/204
Host: Jen Schwarz | Contact: Tyler Engstrom, taengstr@syr.edu
The fact that granular systems are nearly always perched on the verge of mechanical instabilities lends them many surprising material properties; these properties in turn inform phenomena ranging from earthquakes to soft robotics. The jamming transition provides a useful framework for understanding granular matter as well as a wide class of soft matter systems, and computational methods are a natural candidate to study these strongly correlated many-body systems. In this talk I will discuss how the combination of computational techniques with geometrical and topological approaches – including ideas inspired by topological insulators – can teach us something new about both the jamming transition and the rich phenomena of jammed matter itself, as well as potentially lead to the creation of novel mechanical metamaterials.
Massive Gravity and Time-Dependent Black Holes by Rachel Rosen
202 Physics Bldg.
Refreshments at 3:30 pm and the talk starting at 3:45 pm
Host: Prof. Scott Watson / Contact: Yudaisy Salomón Sargentón, 315-443-5960
The predictions of General Relativity (GR) have been confirmed to a remarkable precision in a wide variety of tests. Consistent and well-motivated modifications of GR have been notoriously difficult to obtain. However, in recent years a compelling theory has been shown to be free of the traditional pathologies. This is the theory of massive gravity, in which the graviton is described by a massive spin-2 particle. In this talk I will give a brief review of recent developments in massive gravity. I will then present new results concerning intriguing features of black holes in this theory.
Why Black Holes Matter by Prof. Paul Souder
Aurora Inn (391 Main St., Aurora) on Cayuga Lake
To register, please call 315.685.7163
The intriguing and fascinating world of black holes is the subject of a lecture by nuclear physicist Paul Souder, benefitting the Southern Cayuga Planetarium and Observatory in Aurora, New York. The event is open to the public; however, registration is required. Tickets are $45, and include the lecture, lunch and a silent auction. To register, please call 315.685.7163, or send a check, payable to “Friends of the Southern Cayuga Planetarium,” to P.O. Box 186, Aurora NY 13026. Seating is limited; tickets also are available at the door, while supplies last. For an additional $250, couples may spend the night at the Aurora Inn/E.B. Morgan House or the Rowland House, partaking of wine and cheese with Souder and a continental breakfast the next morning. Space is limited; the deadline to book a room is Wednesday, March 15.
Souder, a professor of physics at Syracuse University, will deliver a multimedia presentation titled “Why Black Holes Matter” on Saturday, April 8, at 11 a.m. at the historic Aurora Inn (391 Main St., Aurora) on Cayuga Lake. He will provide an overview of black holes, as well as share some recent findings, including the discovery of a rare, medium-weight black hole.
Following the lecture, attendees are entitled to a free private tour of MacKenzie-Childs, a Victorian farm that produces high-end tableware and home furnishings, and a $5 wine tasting at Bet the Farm Winery and Gourmet Market.
Proceeds benefit the Friends of the Southern Cayuga Planetarium, a nonprofit organization raising money to restore and reopen the 50-year-old planetarium, closed in 2014.
Non-linear elasticity and relaxation in polymer networks and soft tissues - by Paul Janmey
Rooms 202/204
Host: Jen Schwarz | Contact: Tyler Engstrom, taengstr@syr.edu
The stiffness of tissues in which cells are embedded has effects on cell structure and function that can act independently of or override chemical stimuli. Tissues and the cells within them are subjected strains that often exceed the range of linear viscoelasticity. Rheologic measurements of liver, brain, and adipose tissues over a range of shear, compressive, and elongational strains show that the viscoelastic response of these tissues differs from that of synthetic hydrogels that have similar elastic moduli when measured in the linear range. The shear moduli of soft tissues generally decrease with increasing shear or elongational strain, but they strongly increase under uniaxial compression. In contrast, networks of crosslinked collagen or fibrin soften under compression, but strongly increase shear modulus when deformed in extension. The mechanisms leading to the unusual strain-dependent rheology of soft tissues and fibrous networks do not appear to be explained by current models of polymer mechanics, but appear to relate to local and global volume conservation within the networks and tissues.
40 Years of Lattice QCD
202 Physics Bldg.
Refreshments at 3:30 pm and the talk starting at 3:45 pm
Host: Prof. Jack Laiho / Contact: Yudaisy Salomón Sargentón, 315-443-5960
Lattice QCD was invented in 1973-74 by Ken Wilson, who passed away in 2013. This talk will describe the evolution of lattice QCD through the past 40 years with particular emphasis on its first years, and on the past decade, when lattice QCD simulations finally came of age. Thanks to theoretical breakthroughs in the late 1990s and early 2000s, lattice QCD simulations now produce the most accurate theoretical calculations in the history of strong-interaction physics. They play an essential role in high-precision experimental studies of physics within and beyond the Standard Model of Particle Physics. The talk will include a non-technical review of the conceptual ideas behind this revolutionary development in (highly) nonlinear quantum physics, together with a survey of its current impact on theoretical and experimental particle physics, and prospects for the future.
Fingers, toes and tongues: the anatomy of interfacial instabilities in viscous fluids - by Irmgard Bischofberger
Rooms 202/204
Host: Joseph Paulsen | Contact: Tyler Engstrom, taengstr@syr.edu
The invasion of one fluid into another of higher viscosity is unstable and produces complex patterns in a quasi-two dimensional geometry. This viscous-fingering instability, a bedrock of our understanding of pattern formation, has been characterized by a most-unstable wavelength that sets the characteristic width of the fingers. We have shown that a second, previously overlooked, parameter governs the length of the fingers and characterizes the dominant global features of the patterns. Because interfacial tension suppresses short-wavelength fluctuations, its elimination would suggest an instability producing highly ramified singular structures. Our experimental investigations using miscible fluids show the opposite behavior -- the interface becomes more stable even as the stabilizing effect of interfacial tension is removed. This is accompanied by slender structures, tongues, that form in the narrow thickness of the fluid. Among the rich variety of global patterns that emerge is a regime of blunt structures, "toes", that exhibit the unusual features characteristic of proportionate growth. This type of pattern formation, while quite common in mammalian biology, was hitherto unknown in physical systems.
Very low energy particle physics at CERN: Particle nucleation, planetary albedo, and climate by Neil Donahue
202 Physics Bldg.
Host: Prof. Matthew Rudolph / Contact: Yudaisy Salomón Sargentón, 315-443-5960
In the Cosmics Leaving OUtdoor Droplets (CLOUD) experiment at CERN we study the chemistry and physics leading to particle nucleation in Earth’s atmosphere. Fine particles are important to climate because particles (haze) scatter light and because cloud droplets require water soluble particles to to form in order to overcome the surface tension barrier to droplet formation. For this reason the number of droplets in a cloud depends on the number of particles larger than about 100 nm diameter in the air forming the cloud (the particles must have enough moles of solute to seed a cloud droplet). Clouds with more (smaller) droplets are whiter than those with fewer (larger) droplets, and so they reflect more sunlight back to space. Consequently, the planetary albedo depends on 100 nm diameter particles. The number of particles in air forming clouds has almost certainly changed over the past 250 years since the industrial revolution, and so whiter clouds from pollution are probably masking some portion of potential warming associated with carbon dioxide. At CLOUD we employ a suite of mass spectrometers, particle size spectrometers, and particle number counters to initiate new-particle formation under precisely controlled conditions. We have recently explored the role of highly oxidized organic compounds formed via heretofore unknown chemistry in both particle formation and subsequent particle growth via condensation toward climate relevant sizes. Both are crucial, as tiny, mobile particles must grow rapidly or die by colliding with larger particles.
Cooperative behaviors in living systems: from molecular motors to bacteria - by Agnese Curatolo
Room 208
Host: Cristina Marchetti | Contact: Tyler Engstrom, taengstr@syr.edu
Biology and physics meet in a large variety of different contexts. At all scales, from DNA dynamics to ecological problems, statistical physics provides powerful tools to model and understand the mechanisms leading to collective behaviors so widespread in living systems. In the first part of my talk I will show how to construct the phase diagram of multilane systems which can be used to model molecular motors along microtubules as well as traffic flows of cars or pedestrians. In the second part I will talk about collaborative pattern formation in multi-species bacterial colonies. Our idea is that the control of the cell motilities by the local densities of the different bacterial strains can lead to a variety of patterns with segregation and aggregation between the strains, in the absence of any directional interactions.
SPS colloquium presented by Jack Laiho
202 Physics Bldg.
Host: Patrick Miles/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
I discuss my attempt to reconcile general relativity with quantum theory, i.e. to come up with a quantum theory of gravity. I will give some background on path integrals and running couplings in quantum field theory, and I will explain how these ideas fit into my approach to solve quantum gravity numerically on the computer. I will present numerical results suggesting that we are on the right track.
Signal-to-noise issues in entanglement entropy calculations of ultracold fermions by Joaquin Drut
208 Physics Bldg.
Host: Prof. Simon Catterall / Contact: Yudaisy Salomón Sargentón, 315-443-5960
The LIGO Discovery and Primordial Black Hole Dark Matter by Ely Kovitz
208 Physics Bldg.
Host: Prof. Scott Watson / Contact: Yudaisy Salomón Sargentón, 315-443-5960
The LIGO observatory has recently reported several detections of gravitational waves from the coalescence of binary black holes. We consider the extraordinary possibility that the detected events involving heavier masses are mergers of primordial black holes making up the dark matter in the Universe. We will describe various ways of testing this proposition once more gravitational wave data is gathered, survey some of the existing constraints and present a novel probe of massive compact dark matter in the relevant mass range based on strong gravitational lensing of fast radio bursts. We will conclude with a summary of the observational prospects to test the proposed scenario over the next decade.
Visiting Day for Admitted Graduate Students
202/204 Physics Bldg.
Host: Stefan Ballmer, Tomasz Skwarnicki and Patty Whitmore. Contact: Yudaisy Salomon Sargenton
The Syracuse University Physics department is excited to host our annual Visiting Day for Admitted Students on March 27th. We look forward to meeting the admitted graduate class for Fall 2017 and introducing them to some of the exciting experiences available through our department.
View the Tentative Schedule
Stochastic Particle Production in the Early Universe (with help from disordered wires) by Mustafa Amin
208 Physics Bldg
Host: Prof. Scott Watson / Contact: Yudaisy Salomón Sargentón, 315-443-5960
What do bull sperm know about emergent behaviors? - by Chih-Kuan Tung
Rooms 202/204
Host: Lisa Manning | Contact: Tyler Engstrom, taengstr@syr.edu
In a complex system, some patterns or orders only emerge when the objects interact with the environment or each other. In a dynamical system, the description of how the environmental stress induces the new order can often be described by a bifurcation. In a many-body system, the interaction between individual objects often results in a phase transition or phase separation. These are arguably the most universal descriptions you can find in physics, covering phenomena from Higgs mechanism in high energy, superconductivity in condensed matter, to thermal convection in nonlinear dynamics. Biology provides vast number of different complex systems, yet people only just started to explore finding universality through their emergent behaviors. In this talk, I will focus on two emergent behaviors discovered by using microfluidics to model the physical environment of the mammalian female reproductive tract for sperm. By modeling the outward going fluid flow in the female tract, we showed that sperm swimming against a flow can be described by a bifurcation theory, such that the upstream orientation order only emerges when the flow rate exceeds a critical level, and the emergence follows a ½ power law, which is known for a mean field theory. By adding polymer into the sperm medium to model the viscoelasticity naturally found in the mucus, we found that sperm start to form aggregates, and the formation/dissociation of the aggregates is a dynamic process, similar to a liquid/gas phase separation. This aggregation is primarily mediated by the elasticity of the fluid. I will discuss the implications in both physics and biology.
Imprinting the quantum : Measurement as a route to novel quantum behavior by Mukund Vengalattore
202 Physics Bldg.
Host: Prof. Matthew LaHaye / Contact: Yudaisy Salomón Sargentón, 315-443-5960
The act of measurement can have profound consequences on a quantum system. As such, a quantum system can be controlled and coaxed into novel behavior through the continuous measurement of its properties. I will describe our experimental studies on the measurement-induced quantum control of systems ranging from nanoKelvin atomic gases to millimeter-scale optomechanical systems. In the former case, we show that the quantum evolution of ultracold atomic gases can be controlled and even completely frozen by sporadic measurements - a manifestation of the Quantum Zeno effect. Extending such studies to regimes of dynamically and spatially controlled measurements, we show the emergence of novel phase transitions and critical behavior in the ultracold gas. I will extend these insights to macroscopic optomechanical systems and discuss continuous measurement schemes that allow the quantum state preparation, manipulation and control of macroscopic resonators for applications to quantum sensor technologies and quantum information processing. Professor Mukund Vengalattore is an experimentalist who works in the area of ultra-cold atomic gases and hybrid quantum systems. His talk this week will focus on quantum measurement, including his group’s work on demonstrating the quantum zeno effect with atomic gases and related efforts underway to implement measurement-induced quantum control of optomechanical systems. His abstract and title are pasted below. (Please see the following link for a description of his research and a link to an interview in which he discusses the quantum Zeno effect http://ultracold.lassp.cornell.edu/.
LHCb International Master class
202/204 Physics Bldg.
Host: Prof. Steven Blusk/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
Each year more than 13.000 high school students in 52 countries come to one of about 200 nearby universities or research centres for one day in order to unravel the mysteries of particle physics. Lectures from active scientists give insight in topics and methods of basic research at the fundaments of matter and forces, enabling the students to perform measurements on real data from particle physics experiments themselves. At the end of each day, like in an international research collaboration, the participants join in a video conference for discussion and combination of their results. Syracuse University is one of the hosting sites on March 17, 2017. For more information, click here
LHCb International Master class
202/204 Physics Bldg.
Host: Prof. Steven Blusk/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
Each year more than 13.000 high school students in 52 countries come to one of about 200 nearby universities or research centres for one day in order to unravel the mysteries of particle physics. Lectures from active scientists give insight in topics and methods of basic research at the fundaments of matter and forces, enabling the students to perform measurements on real data from particle physics experiments themselves. At the end of each day, like in an international research collaboration, the participants join in a video conference for discussion and combination of their results. Syracuse University is one of the hosting sites on March 13, 2017. For more information, click here
Neutrinos as the key to the universe as we know it by Yuval Grossman
202 Physics Bldg.
Refreshments at 3:30 pm and the talk starting at 3:45 pm
Contact: Yudaisy Salomón Sargentón, 315-443-5960
There are three open questions in physics which seem unrelated: Why is there only matter around us? How neutrinos acquire their tiny masses? Why all particles in Nature have integer electric charges? It turns out that these open questions maybe related. In this talk I will explain these open questions, the connection between them, and describe the on-going theoretical and experimental efforts in understanding them.
Imaging currents in two-dimensional quantum materials - by Katja Nowack
Rooms 202/204
Host: Britton Plourde | Contact: Tyler Engstrom, taengstr@syr.edu
Magnetic imaging is uniquely suited to the non-invasive imaging of current densities, particularly in two-dimensional devices. In this talk, I will showcase this approach by discussing measurements on HgTe quantum well devices in the quantum spin Hall (QSH) regime. In a nutshell, we scan a superconducting quantum interference device (SQUID) to obtain maps of the magnetic field produced by the current flowing in a device. From the magnetic image we reconstruct a two-dimensional current distribution with a spatial resolution of several microns. This allows us to directly visualize that most of the current is carried by the edges of the quantum well devices when tuned into their insulating gaps - a key feature of the QSH state. I will discuss routes towards improving the spatial resolution of the current images to sub-micron length scales through a combination of improved image reconstruction and smaller sensor sizes and outline opportunities for current imaging in a range of materials including graphene and magnetically doped topological insulators.
The Scintillating Science of Long-Baseline Neutrino Experiments by Denver Whittington
202 Physics Bldg.
Refreshments at 3:30 pm and the talk starting at 3:45 pm
Host: Prof. Mitchell Soderberg/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
This colloquium will present an overview of neutrino oscillations and the physics reach afforded by these long-baseline neutrino experiments. I will discuss recent and upcoming results from NOvA, facilitated by advanced image recognition tools for event classification. I will also cover the design and prospects of DUNE, including some of the unique challenges of scintillation light detection in liquid argon.
Searching for CP-Violation with the DUNE Experiment by Dan Cherdack
202 Physics Bldg.
Refreshments at 3:30 pm and the talk starting at 3:45 pm
Host: Prof. Mitchell Soderberg/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
The weak interaction is one of the four fundamental forces that govern our universe. While the effects of this force are more subtle than the other three, the weak force has many interesting properties that the other three forces do not. For example, the weak interaction can change particle flavor, it maximally violates parity symmetry, and it even violates charge-parity (CP) symmetry, which introduces differences between matter and antimatter. These differences may explain the matter-antimatter asymmetry of the universe, and in turn validate the big bang theory. Neutrinos only interact via the weak force which means they are hard to detect, but provide a unique test bed for studying the weak interaction. Over the past few decades it was discovered that neutrinos have mass and change flavors. Studying the way neutrinos change flavors, termed neutrino oscillations, allows us to search for a new source of CP-violation. The next-generation Deep Underground Neutrino Experiment (DUNE) will usher in an era of high precision neutrino physics with the worlds most intense neutrino beam and high resolution Liquid Argon (LAr) Time Projection Chamber (TPCs) detectors. The Fermilab Short-Baseline Neutrino (SBN) Program will employ three LAr TPCs, which will provide and excellent test bed for LAr TPC R&D, and allow for many important measurements crucial to DUNE. I will discuss the theoretical framework we use to describe neutrino oscillations, and the exciting opportunities and new challenges afforded us by these experiments.
Lipid organization in model membranes and living cells by Jonathan Nickels
202 Physics Bldg.
Refreshments at 3:30 pm and the talk starting at 3:45pm
Host: Prof. Lisa Manning/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
The structure and function of biological membranes has been studied for more than 100 years, but only recently has the existence and role of lipid organization been recognized. Lateral lipid organization, often called domains or lipid rafts, are hypothesized to act as scalable compartments in biological membranes, providing appropriate physical environments to their resident membrane proteins. This implies that lateral lipid organization is associated with a range of biological functions, such as protein co-localization, membrane trafficking, and cell signaling, to name just a few. Because of these connections, there exists an unrealized potential to unlock new understanding and therapies to a variety of diseases based on an improved grasp of the structure and biophysical basis of lipid raft formation and properties. This potential is tempered by a number of observational difficulties for the experimental biophysicist. Their nanoscopic size, compositional similarity with the surrounding lipids, as well as the potentially perturbing effects of some molecular probes, all limit the amount of information that can be obtained about lipid rafts from common biophysical techniques. Neutron scattering techniques have proven to be a uniquely useful tool to get around these limitations. In this talk, I will discuss recent work using scattering and simulation approaches to study lipid domains in model membrane systems. These experimental observations and subsequent analysis are significant in the context of understanding what physical mechanisms underlay the formation and stability of nanoscopic lipid heterogeneities. This work lead into current efforts to probe the structure and organization of the cell membrane in a living organism, B. subtilis, by extending these scattering based approaches in combination with a number of innovative genetic and biochemical strategies. This approach has already yielded the first direct in vivo observations of bilayer hydrophobic thickness as well as evidence for the existence of lipid rafts in this organism. Together, these approaches are establishing a platform for systematic in vitro and in vivo investigations of cell membrane organization; setting the stage to both understand and access the potential of these enigmatic membrane structures.
Life in Suspense: Particle dynamics in suspensions of swimming bacteria by Alison E. Patteson
202 Physics Bldg.
Host: Prof. Lisa Manning/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
Cells and microorganisms move in diverse environments that range from simple pond and ocean water to complex biological fluids, such as mucus. These environments frequently contain passive particles, such as macromolecules, flexible polymers, or colloids, which can influence cell motility and function. Interactions between cells and particles underlie many aspects of medicine, biology, and engineering, including the spread of bacterial infections, the formation of biofilms, and the design of swimming micro-robots. I use particles (1-10 micron) and polymer molecules (<1 micron) to experimentally investigate particle-bacteria interactions in suspensions of swimming Escherichia coli. By varying the size of passive spherical particles, I find an anomalous diffusive regime in E. coli suspensions, in which larger particles diffuse faster than smaller particles. This feature arises due to an interplay between the particle’s Brownian diffusion and convection through bacterial interactions. When flexible polymers are added to the suspending fluid, the E. coli drastically change their swimming behavior: cells swim faster and tumble less often, drastically enhancing their translational diffusion. By varying polymer molecular weight, I find that fluid viscosity suppresses cell tumbling while fluid elasticity increases swimming speed. I demonstrate that E. coli produce elastic stresses in the fluid by visualizing fluorescently-labeled DNA polymers, which deform and stretch under the applied flows generated by a single E. coli. Together these results uncover new avenues of transport in active fluids, which can be used to control the spread of bacteria or the dispersion of particles in microbial environments. I discuss applications to particle sedimentation and explore how crawling mammalian cells move through and interact with small tissue-like pores.
Artificial Membrane Nanopores Made from DNA: Nanostructures for Synthetic Biology, Cancer Research, and Single-Molecule Sensing - by Stefan Howorka
Rooms 202/204
Host: Liviu Movileanu | Contact: Tyler Engstrom, taengstr@syr.edu
Membrane nanopores and ion channels are essential in cells and control the transport of molecular cargo across bilayers. Replicating biological channels with artificial, rationally designed nanostructures can open up new applications. I describe the generation of stable self-assembled DNA nanopores that insert into lipid bilayers to facilitate transport across the membranes. The DNA channels are composed of interlinked duplexes and carry lipid anchors to hold the negatively charged channels in the membrane(1,2,3). One DNA version mimics the function of biological ligand-gated ion channels where a DNA ligand can re-open the channel(2). The pore can also distinguish with high selectivity the transport of small-molecule cargo that differs by the presence of a positive or negative charge. The synthetic analogue may be used for controlled drug release and the building of cell-like networks. Related DNA channels show other hallmarks of the biological templates such as voltage-gating at high transmembrane potentials(2,3,4). The artificial pores can furthermore be programmed to function as cytotoxic agents by killing cancer cells via membrane-rupturing(5). The synthetic pores expand the range of other DNA nanostructures that mimic biological functions of membrane proteins to control bilayer and cell shape(6). References: (1) Nano Lett. 2013 13 2351; Angew. Chem. Int. Ed. 2013 52 12069. (2) Nat. Nanotechnol. 2016 11 152. (3) ACS Nano 2015 9 1117. (4) ACS Nano 2015 9 11209. (5) Angew. Chem. Int. Ed. 2014 53 12466; Nat. Chem. 2014 7 17. (6) Science 2016 352 890.
Exploring ν Territory: Using LArTPC Technology by Yun-Tse Tsai
202 Physics Bldg.
Refreshments at 3:30 pm and the talk starting at 3:45 pm
Host: Prof. Mitchell Soderberg/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
Neutrinos are the electrically neutral elementary particles with finite mass. The discovery of the non-zero masses is the first instance of a conflict with the Standard Model of particle physics, which has successfully described elementary particles and interactions but leaves questions unanswered. The fruitful results from neutrino experiments in the past two decades have opened a window to a new territory, and further measurements are required to address fundamental questions. In this talk, I will introduce the core topics of neutrino physics, the requirements of neutrino experiments, focusing on the technology of liquid argon time projection chamber (LArTPC). In particular, I will discuss measuring neutrinos from supernova explosions. I will talk about the MicroBooNE experiment, the first large LArTPC in the U.S., its recent results, and the future LArTPC experiments.
Wilson Loops and the Loop Equation by Peter Anderson
202 Physics Bldg.
Host: Prof. Simon Catterall / Contact: Yudaisy Salomón Sargentón, 315-443-5960
Pure gauge theories can be formulated in terms of Wilson Loops correlators by
means of the loop equation. In the large-N limit this equation closes in the
expectation value of single loops. In particular, using the lattice as a
regulator, it becomes a well defined equation for a discrete set of loops. Here
we present our development of a numerical method to calculate bounds for the
expectation values of the Wilson loops in both the weak and the strong coupling
regimes. Our method uses the loop equation and the observation that certain
matrices of Wilson Loop expectation values are positive definite. We show how in
the exactly solvable case of two dimensions this approach gives very good
results by considering just a few loops. In four dimensions it gives good
results in the weak coupling region and therefore is complementary to the strong
coupling expansion. Applications to future SUSY lattice studies are then
discussed.
Soft matter approaches to biology: A tale of mucus hydrogel in human lung defense by Liheng Cai
202 Physics Bldg.
Refreshments at 3:30 pm and the talk starting at 3:45pm
Host: Prof. Lisa Manning/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
Biological systems are featured by their ability to defend themselves against external challenges. While these defense mechanisms are extensively studied in the context of life sciences, their physical aspects have largely been overlooked, although they are implicated in many important biological processes. Using knowledge and tools in soft matter and physical science, we can not only provide unique insights to biological questions that directly impact healthcare, but also in turn create new directions that broaden the scope of soft matter research. In this talk, I will discuss how soft matter physics can help understand a long-standing question for human lung defense: How can the human lung fight against numerous inhaled infectious particulates and maintain functional through its lifetime? Contrary to the widely accepted dogma that the epithelium of human airway is lined by a physiological liquid, I discover that it is covered by a gel-like polymer brush. This brush layer protects the epithelium from small, infectious particulates that sneak through mucus hydrogel. Moreover, the brush layer enables efficient clearance of mucus out of lung by stabilizing itself against osmotic compression from the mucus. Furthermore, I will show that chronic osmotic stress from diseased mucus likely affects airway remodeling. It slows down the proliferation of epithelial cells, and more strikingly, directs the differentiation of epithelial cells to mucus producing cells, a hallmark of mucus obstructive lung diseases such as asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis. These findings suggest that the osmotic pressure of mucus hydrogel provides a unified measure of pathogenesis of mucus obstructive lung diseases, and open new directions for the development of novel therapeutics to teat these diseases.
Stationary hydrodynamics of Marangoni driven spreading of liquids at air-water interfaces by Mahesh Bandi
202 Physics Bldg.
Refreshments at 3:30 pm and the talk starting at 3:45pm
Host: Prof. Lisa Manning/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
A drop of liquid with lower surface tension than water will spread radially outwards when introduced at an air-water interface, to minimise the interfacial energy. If the liquid drop is insoluble in water (e.g. oil), the transient spreading halts once the liquid covers the surface; a phenomenon with rich theory supported by satisfactory experimental evidence. However if a mechanism exists whereby the spreading liquid can leave the interface (e.g. via dissolution or evaporation), a stationary flux is achieved — the liquid entering the interface (influx) spreads radially over some distance before steady-state flux balance is attained as it leaves the interface (outflux). Not much is known about such processes despite their relatively common occurrence in nature. Although soluble, such surfactants can spread through a phase adsorbed to the interface, requiring a distinction between two clearly different spreading possibilities. In this talk, I will explain our theoretical and experimental investigations to understand these processes. Scaling analysis helps discriminate between the spreading mechanisms, which we verify with experiments.
Mind the gap: a new kind of fingering instability in colloidal rollers by Michelle Driscoll
202 Physics Bldg.
Refreshments at 3:30 and the talk starting at 3:45pm
Host: Prof. Lisa Manning/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
When colloidal particles are rotated adjacent to nearby floor, strong advective flows are generated around them, even quite far away. When a group of these microrollers is driven, the strong hydrodynamic coupling between particles leads to formation of new, emergent structures: an initially uniform front of microrollers evolves first into a shock, which then quickly becomes unstable, emitting fingers of a well-defined wavelength. Our experiments and simulations confirm that this instability is very different than typical fingering instabilities, where size scale selection is a consequence of competing stresses. In this case, the instability arises only due to hydrodynamic interactions, and it is controlled by a single geometric parameter: the particle-floor gap. We have developed a simplified continuum model that reproduces the instability behavior. This model confirms that instability we observe in the experiments is indeed a direct consequence of the inward flows created by the interactions between the particles and the nearby solid surface.
A string-like construction of scalar field theory amplitudes by Poul Henrik Damgaard
233 Physics Bldg
Host: Prof. Simon Catterall / Contact: Yudaisy Salomón Sargentón, 315-443-5960
Think Super: Artificial Neurons made from Superconductors - by Ken Segall
Rooms 202/204
Host: Britton Plourde | Contact: Tyler Engstrom, taengstr@syr.edu
Our research focuses on the design, fabrication and testing of integrated circuits which can simulate neuron spiking dynamics on very fast timescales. These circuits are based on a low-temperature, superconducting electronics technology (Josephson junctions) that has already been successful in creating ultra-sensitive magnetometers, high-performance radiation detectors, high-speed digital processors, and the primary voltage standard in the U.S. The short spiking times in these artificial neurons combined with analog scaling properties give this approach a potentially unprecedented ability to investigate long term dynamics of large networks. In addition, these artificial neurons dissipate almost no power, making them a candidate for a low-power, neuromorphic computing technology. We have performed the first experiments on two superconducting neurons which are mutually coupled with artificial axons and synapses. In some regions of parameter space the neurons are desynchronized. In others, the Josephson neurons synchronize in one of two states, in-phase or anti-phase. An experimental alteration of the delay and strength of the connecting synapses can toggle the system back and forth in a phase-flip bifurcation. Firing synchronization states are calculated >70,000 times faster than conventional digital approaches. With their speed and low energy dissipation (10-17 Joules/spike), this set of proof-of-concept experiments establishes Josephson junction neurons as a viable approach for improvements in neuronal computation as well as applications in neuromorphic computing. A Lithographic Superconducting Circuit Interconnected Neurons
Discovering the Undetectable: (Sterile) Neutrino Oscillations by Joseph Zennamo
202 Physics Bldg.
Refreshments at 3:30 pm and the talk starting at 3:45 pm
Host: Prof. Mitchell Soderberg/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
Since their discovery in 1956 neutrinos have remained an enigma. Proposed in 1930 to explain the energy spectrum of electrons emerging from nuclear decays it was not until 1998 that they were discovered to have mass. The difficulty of studying neutrinos is driven by the fact that they rarely interact, requiring large detectors and intense sources. This colloquium will discuss the continued puzzles which neutrinos provide us and how we can search for the existence of a new neutrino with an experimental program being built at Fermilab, the Short-Baseline Neutrino Program.
Kameshwar C. Wali Lecture in the Science and Humanities - Inside the Brain - Synapses Lost and Found in Development and Alzheimers Disease by Dr. Carla J. Shatz
Lyman 132
Host: Cristina Marchetti and A. Alan Middleton | Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu
Adult brain connections are precise, but precision emerges during developmental critical periods as synapses - the delicate contacts between neurons that relay and store information - are either pruned away or grow in a process driven by learning. Understanding the molecules and mechanisms of synapse pruning may lead to treatments for developmental disorders and Alzheimer’s disease. Connections in the adult brain are precise, but do not start out that way. Precision emerges during developmental critical periods as synapses - the delicate contacts between neurons that relay and store information - are either pruned away or grow in a process driven by learning. An unexpected set of molecules once thought only to function in the immune system was discovered in neurons and found to regulate pruning. Blocking the function of these molecules not only reopens a critical period for vision in adult brain, but also protects against memory loss in mice models of Alzheimer’s disease. New avenues for treating developmental disorders and AD may come from understanding the function of these molecules in the brain.
Active Matter on Curved Surfaces - by Yaouen Fily
Rooms 202/204
Host: Cristina Marchetti | Contact: Matthias Merkel, mmerkel@syr.edu
Unlike bird flocks, whose motion in the sky cares little about boundaries, most active systems exist within confined spaces. For example, the cytoskeleton is bounded by the cell membrane, and the motion of cells within an organism in constrained by neighboring tissues. Such confinement, it turns out, can have profound effects, and those effects are very sensitive to the geometry of the boundaries. In this talk I will discuss how the response of active systems to the geometry of their confinement arises from the dynamics of their active constituents along the boundaries and how to relate the dynamics along the boundaries to the macroscopic properties of the system (e.g., density, pressure).
Physics Department Holiday Party
Inn Complete
Yudaisy Salomón Sargentón, yssargen@syr.edu, 315-443-5960
The Bonn Physics Show -- By Students for Kids, an Exciting Outreach and Education Project by Herbert Dreiner
Rooms 202/204
Host: Jay Hubisz / For other questions: Yudaisy Salomón Sargentón, yssargen@syr.edu, 315-443-5960
The Bonn Physics show started in Dec. 2001. The special thing about our show is that it is developed and performed by Bonn university physics students. For me as a professor the primary target group are the university students. Since 2001 we have been performing a new physics show in Bonn, every year. The show is addressed at kids aged 10 and older. With the experienced physics students we have developed many spin-offs: e.g. YouTube films, Science Slams, building new demo experiments. Importantly, we have also developed more advanced shows in particular about elementary particle physics. The most recent show on particle physics involves more than 25 live experiments and is embedded in a historical story line. With various shows we have travelled across Germany (Berlin, DESY, Heidelberg, Deutsches Museum München) and more recently also across Europe: CERN, Oxford, London, Padua, Trieste, as well as Copenhagen and Beijing, China. We show a few experiments here live, as well as films of experiments. We try to emphasize the essential features of a successful show and give some advice on how to set up your own show, involving the local physics students.The Bonn Physics Show -- By Students for Kids, an Exciting Outreach and Education Project
Thesis/ Dissertation Title: High Energy Neutron Backgrounds for Underground Dark Matter Experiments by Yu Chen
202 Physics Bldg.
Advisor: Prof. Richard Schnee / Contact: Yudaisy Salomón Sargentón, 315-443-5960
Surprises in Non-Minimal Cosmologies by Jeffrey Kost
202 Physics Bldg.
Host: Prof. Scott Watson / Contact: Yudaisy Salomón Sargentón, 315-443-5960
Light scalar fields such as axions and string moduli can play an important role in early-universe cosmology. However, many factors can significantly impact their late-time cosmological abundances. For example, in cases where the potentials for these fields are generated dynamically — such as during cosmological mass-generating phase transitions — the duration of the time interval required for these potentials to fully develop can have significant repercussions. Likewise, in scenarios with multiple scalars, mixing generated amongst the fields can also give rise to modifications of the resulting late-time abundances. While previous studies have focused on these effects in isolation, surprising new features arise from the interplay between them. These include large suppressions in the late-time scalar abundance --- even by many orders of magnitude --- as well as parametrically-resonant enhancements, and a ``re-overdamping'' phenomenon which causes the energy density to behave in ways that differ from pure dark matter or vacuum energy. In this talk, I shall discuss the origins and implications of these effects, and how they can appear in situations in which our scalar fields form an entire Kaluza-Klein tower.
Active Matters: probing forces, fluctuations and self-organization in biological systems - by Nikta Fakhri
Rooms 202/204
Host: Lisa Manning | Contact: Matthias Merkel, mmerkel@syr.edu
Biological functions rely on ordered structures and intricately controlled collective dynamics. Such order in living systems is typically established and sustained by continuous dissipation of energy. The emergence of ordered patterns of motion is unique to non-equilibrium systems and is a manifestation of dynamic steady states. Many cellular processes require transitions between different steady states. Can general principles of statistical physics guide our understanding of such cellular self-organization? In this talk, I will show model actomyosin cortices, in the presence of rapid turnover, self-organize into three non-equilibrium steady states as a function of network connectivity. The different states arise from a subtle interaction between mechanical percolation of the actin network and myosin-generated stresses. I will discuss our experimental approach to identify governing principles of collective dynamics, spatiotemporal stress pattern formation and energy dissipation in such far from equilibrium biological systems.Abstract
Title: Did LIGO Detect Dark Matter? by Dr. Simeon Bird
202 Physics Bldg.
There is a possibility that the recent LIGO detection of gravitational waves originated from the merger of two primordial black holes, making up the dark matter. Thirty solar mass black holes, as detected by LIGO, lie within an allowed mass window for primordial black hole dark matter. Interestingly, our best estimates of the number of observable mergers fall within the range implied by current LIGO data. I will explain these estimates, discuss the (considerable!) theoretical uncertainties, and finish with prospects for testing the model.
Undergraduate Research Day 2016
Rooms 202/204
Host: Prof. John Laiho jwlaiho@syr.edu / Contact: Yudaisy Salomón Sargentón, 315-443-5960
We are pleased to announce the tenth annual Undergraduate Research Day (URD) at Syracuse University. This year’s meeting will be held on Saturday, November 12, 2016. In recent years, more than 100 students from 16 colleges and universities have participated in URD. The meeting gives undergraduates a chance to present their own research (via talks or posters) and meet with other students and professors from New York area universities and beyond. All students are encouraged to give a talk! To find out more and register, click here
Phonons in Confined Active Chains - by Eva Kanso
Rooms 202/204
Host: Jen Schwarz | Contact: Matthias Merkel, mmerkel@syr.edu
I will discuss two problems in fluid mechanics inspired by biological systems. The first problem concerns the emergent global patterns of active particles (swimmers) confined in microfluidic channels. I will show interesting transitions in the global patterns, including the development of density shock wakes in two-dimensional channels and phonons in one-dimensional active chains. The second problem is that of an inertial flyer hovering in an oscillatory flow. I will discuss stability and maneuverability of the flyer, and argue that these two properties need not be seen as disjoint. Abstract
Brightman Professorship Ceremony
Rooms 202/204 Physics Bldg.
Hosts: Dean Karin Ruhlandt, Chancellor Kent Syverud.
TBD by Atsuhisa Ota
Rooms 202
Host: Prof. Scott Watson / Contact: Yudaisy Salomón Sargentón, 315-443-5960
Really condensed matter: problems in the physics of neutron star crusts and white dwarf interiors - by Tyler Engstrom
Rooms 202/204
Host: Jen Schwarz | Contact: Matthias Merkel, mmerkel@syr.edu
Precision measurements of a half-dozen different kinds of astrophysical phenomena can potentially probe a neutron star crust's material properties, including elastic constants, transport coefficients, and equation of state. Condensed matter theory dealing with extreme pressures and huge magnetic fields (~1012-1015 gauss) might thus be tested in this "laboratory." After giving an overview of the phenomena, I will describe two toy models of electrons and nuclei in huge magnetic fields: a nonlinear Thomas-Fermi model of the lowest Landau level, and a nearly free electron model containing magnetic commensurability effects. The former predicts a large shear modulus enhancement compared to the linearly-screened Coulomb crystal, and the latter hints at the existence of stellar layers in which transport anisotropy is reduced, i.e. heat spreading layers. Next we will turn to 3-component accreted crusts and 3-component white dwarfs (in particular, type 1a supernova progenitors). A global genetic search of composition and structure predicts several new astrophysically-relevant crystal structures; these are included in a new, self-consistent coupling of the phase stability and stellar structure problems (for white dwarfs). Equilibrium phase layering diagrams are computed.
MSSM4G: Reviving Bino dark matter with vector-like 4th generation fermions
Rooms 202
Host: Jay Hubisz / Contact: Yudaisy Salomón Sargentón, yssargen@syr.edu, 315-443-5960
We show that by supplementing the MSSM with vector-like 4th generation copies of standard model fermions we can simultaneously extend the viable mass range of Bino dark matter and alleviate the fine tuning in the Higgs sector. The extra requirement of perturbative gauge coupling unification restricts such models to only two, both of which are consistent with current data in most of the parameter space. The current bounds and future prospects of direct detection, indirect detection and collider searches will be discussed.
Quantum information processing with 4 electrons and 1 million nuclei - by John Nichol
Rooms 202/204
Host: Matthew LaHaye | Contact: Matthias Merkel, mmerkel@syr.edu
Individual spins in semiconductors can retain their quantum phase coherence for times exceeding one second. Such long coherence times makes spins a versatile platform for exploring quantum information processing and condensed matter physics. I will discuss recent work exploiting the joint spin-state of two electrons in a GaAs double quantum dot as a spin qubit. This qubit is highly sensitive to its local magnetic environment. We leverage this sensitivity to precisely measure the statistically fluctuating nuclear polarization in the semiconductor crystal. Surprisingly, we can harness the random nuclear polarization in the semiconductor to suppress electrical decoherence in the spin qubit, enabling a high-fidelity entangling gate between spin qubits.Abstract
Asymmetric reheating and chilly dark sectors by Peter Adshead
Rooms 233
Host: Prof. Scott Watson / Contact: Yudaisy Salomón Sargentón, 315-443-5960
Biophysical force regulation in tumor cell invasion - by Mingming Wu
Rooms 202/204
Host: Cristina Marchetti | Contact: Matthias Merkel, mmerkel@syr.edu
In native states, animal cells of most types are surrounded by extracellular matrices (ECMs). Cells are physically linked to the ECM fibers via adhesion molecules. Indeed, mechanical interactions between animal cells and ECM critically regulate cell functions, and disruption of the cell-ECM crosstalk is implicated in pathologic processes including tumor progression and fibrosis. Physical forces that cells generate within a 3D ECM is a key mediator between the cell and its microenvironment. In this talk, I will describe efforts in my lab (biofluidics.bee.cornell.edu) in understanding how biophysical forces regulate cell-ECM interaction, and modulate cancer cell invasion within a three dimensional architecture. Two examples will be given. (1) Using a newly developed 3D traction force microscopy, we measure forces generated by single cells when embedded within natively derived collagen matrices. We find that fibrous nonlinear elasticity of collagen matrix enables a positive mechanical feedback between the cell and ECM, and promotes a long range cell-cell interaction. (2) Using a microfluidic model, we demonstrate that interstitial fluid flow stress regulates tumor cell invasion within an ECM. We find that cells change motility types when subjected to fluid flows. Our work begins to elucidate the basic governing principles of physical forces in mediating cell-ECM interactions at single cell level, and opens doors for modelling population level cell dynamics in 3D.Abstract
Title: Part 1: A theoretical physicist in industrial R&D. Part 2: Monte Carlo correction of an estimated renormalized Hamiltonian by Robert Cordery
Rooms 202/204
Host: Simon Catterall / contact: Yudaisy Salomon Sargenton, 315-443-5960
(1) How theoretical physics training prepares you for a career in an industrial R&D group - that is not concerned with theoretical physics. (2) I will present an alternate Monte Carlo Renormalization Group (MCRG) approach based on a guessed renormalized Hamiltonian. A renormalization group transformation maps a site Hamiltonian that describes a system on a small length scale to a renormalized block Hamiltonian that describes the system on a larger length scale. MCRG typically compares correlations of block and site variables rather than directly calculating the block Hamiltonian. In this alternate approach we simulate a system with both block and site variables. The simulation includes the site Hamiltonian, the coupling to the block variables, and subtracts an estimate of the block Hamiltonian. This eliminates both long distance correlations and critical slowing down. The method uses a single transformation. The renormalized Hamiltonian is calculated directly.
Colloquium Double-Header by Professors Steven M. Block and Robert H. Austin
Room 202/204 Physics
Host: Prof. Liviu Movileanu. For other questions: Yudaisy Salomon Sargenton, yssargen@syr.edu
Steven M. Block, Ph.D. Advances have led to the new field of single molecule biophysics. Single-molecule techniques can record characteristics that are obscured by traditional biochemical approaches, revealing behaviors of individual biomolecules. Prominent among the techniques is the laser-based optical trap, or ‘optical tweezers,’ which uses radiation pressure. Optical traps now measure biomolecular properties with a precision down the atomic level—achieving a resolution of 1 angstrom over a bandwidth of 100 Hz—while exerting controlled forces in the piconewton range. Among the successes for optical traps have been measurements of the steps produced by motor proteins (for example, kinesin and myosin) and by processive nucleic-acid enzymes (for example, RNA polymerase), as well as determinations of the strengths of noncovalent bonds between proteins, and the kinetics of structure formation by DNA and RNA. Optical trapping instruments have been particularly useful in mapping the energy landscapes for folding macromolecules. We’re now able to follow the co-transcriptional folding of RNA in real time, as it is synthesized, revealing how such folding can regulate downstream genes, mediated by structured RNAs called ‘riboswitches.’ In recent developments, optical traps have been used in conjunction with single-molecule FRET (Förster Resonance Energy Transfer) to report on folding configurations and internal degrees of freedom in biomolecules. Robert H. Austin No bacterium is an island. The bacterium E. coli’s motility not only responds to a number of input parameters (5 chemicals, heat, maybe pressure, maybe electric field), and it modifies these parameters by virtue of metabolism, movement and growth. The result is that bacteria interact in a collective manner. My most recent question is: do bacteria collectively compute in some sense solutions to biological and physical problems? I’ll show how we have used microfabrication techniques to probe the problem solving abilities in a collective manner. I’ll speculate that this insight can be applied (perhaps) to how antibiotic resistance arises, and how cancer cells evade chemotherapy in a tumor.
S.W. Ascherman Professor of the Sciences
Department of Applied Physics
Department of Biology
Stanford University CA 94305Optical Tweezers: Gene Regulation, Studied One Molecule at a Time
Professor of Physics
Department of Physics
Princeton UniversityThe Collective Brain of Bacteria and Applications to Antibiotics and Cancer
Spontaneous and induced cell polarization and collective migration - by Alex Mogilner
Rooms 202/204
Host: Jen Schwarz | Contact: Matthias Merkel, mmerkel@syr.edu
Fish keratocyte cells served as the model system to understand biophysics of cell motility for decades. Recently, we combined experiment and modeling to understand the mechanism of polarization of these cells. We found that two essential feedbacks - positive one between myosin density and actin flow, and negative one between stick-slip adhesions and actin flow - underlie the motility initiation. Interestingly, keratocytes polarize in electric fields much faster but not stably, through different mechanism. I will also describe preliminary results on collective keratocyte migration in electric fields.Abstract
Physics Department Fall Annual Picnic
Green Lakes State Park-Reserve Shelter
Physics Department Welcome Reception
Rooms 202/204
Yudaisy Salomón Sargentón, yssargen@syr.edu, 315-443-5960
Please join us in this tradition to greet new staff, students, and faculty. This event is a great way to start the year, to catch up with people, and to grab a bite of cake. If you are new to the Department within the last year, be prepared to say hello to everyone. I do hope you can participate and meet the new members of our Department.Physics Department Welcome Reception 2016
Department Training and Orientation (Aug 22 - Aug 25)
202/204 Physics Bldg.
Comprehensive Exam (August 20 and 21st)
202/204 Physics Bldg.
Comprehensive Exams for ALL INCOMING STUDENTS (Prof. Carl Rosenzweig) Part I-Saturday; Part II-Sunday.
Programming Mechanical Metamaterials
202/204 Physics
Host: Jennifer Schwarz | Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu
Mechanical metamaterials have novel elastic and acoustic properties--negative Poisson's ratios and compressibilities, phononic bandgaps, bistability and acoustic lensing--which derive from their structure. Properties may be made robust by linking them to the system's topological state, in which the global structure determines and protects a particular mechanical response, equivalent to the behavior of electronic systems such as topological insulators. Topologically nontrivial states may be achieved in virtually any marginally rigid (isostatic) structure and at any scale: hinged frames, jammed packings, 3D-printed structures, origami/kirigami, self-assembled lattices and oscillator networks. The immediate effect of topologically polarizing such a system is to create protected floppy edge modes. The ultimate goal is to manufacture systems with arbitrary programmed mechanical responses that are robust against disorder and fluctuations. I will describe two recent advances: (1) Creating materials with bulk topological modes and (2) Exploiting global mechanical instabilities to alter the topological state. In the first case, I describe lattices (the equivalent of Weyl semimetals) that possess topologically-protected bulk zero modes, leading to a sinusoidal elastic instability at incommensurate wavelength. In the second case, I consider systems with global elastic instabilities and show that the nature of such an instability determines much of the lattice's mechanical and acoustic properties, such as the structure of its edge modes. Finally, I show that extending this instability into the nonlinear regime can alter the topological polarization, hence tuning the edge stiffness by many orders of magnitude.
The 3 Dimensional Structure of the Nucleon - Extracting Spin Dependent Parton Distributions from Deeply Virtual Scattering Processes
202 Physics
Host: Kamesh Wali, wali@phy.syr.edu | Contact: David Schaich, daschaich@gmail.com
Spin and transverse momentum dependent parton distributions - GPDs, TMDs and GTMDs - are at the interface between the non-perturbative regime of QCD hadron structure and observable quantities. The distributions appear as linear superpositions and convolutions within helicity amplitudes for parton-nucleon scattering processes, which, in turn, occur in amplitudes for leptoproduction processes. The phenomenological extraction of the amplitudes, and hence the distributions, is a challenging task. We will present relations between crucial quark-nucleon or gluon-nucleon helicity amplitudes and the rich array of angular distributions in Deeply Virtual Compton Scattering, Time-like Compton Scattering and novel Multi-hadron photon processes. These provide an important window into the 3 dimensional momentum and spin structure of the nucleons.
Prototyping Extensible Quantum Computing Architectures
202/204 Physics
Host: Britton Plourde | Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu
Quantum computing architectures with ten or more quantum bits (qubits) have been implemented using trapped ions and superconducting devices. The next milestone in the quest for a quantum computer is the realization of quantum error correction codes. Such codes will require a very large number of qubits that must be controlled and measured by means of classical electronics. One architectural aspect requiring immediate attention is the realization of a suitable interconnect between the quantum and classical hardware. In this talk, I will introduce the quantum socket, a three-dimensional wiring method for qubits with superior performance as compared to two-dimensional methods based on wire bonding. The quantum socket is based on spring-mounted micro wires – the three-dimensional wires – that connect electrically to a micro-fabricated chip by pushing directly on it. The wires have a coaxial geometry and operate well over a frequency range from DC to 10 GHz. I will present a detailed characterization of the quantum socket, with emphasis on generalized time-domain reflectometry, a new signal integrity tool developed in my lab. As a proof of concept for quantum computing applications, I will show a series of experiments where a quantum socket was used to measure superconducting resonators at a temperature of ~10 mK. I will also show preliminary results where a socket was used to characterize resonators fabricated from molecular beam epitaxy aluminum films on gallium arsenide substrates. In conclusion, I will give an outlook demonstrating how the quantum socket can be used to wire a quantum processor with a 10 × 10 qubit lattice and I will outline our present work toward the implementation of such a lattice.
Do you tell the truth about your age? When sediments lie… A play told in three acts
202/204 Physics
Host: Scott Watson | Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu
Considerable progress has been made in developing methods to determine the source areas of sedimentary rocks. We have moved from qualitative characterization of sandstone, to trace element chemistry of shale, to the isotope composition of clastic igneous rocks, and now to determining the age of zircon crystals smaller than the width of a hair. Detrital zircon geochronology has become so popular that there are now well over 200,000 published detrital zircon ages. However, sometimes sediments lie… The age distribution of zircon in many sandstones and much modern alluvium is dominated by ages of 1.3 – 1.0 Ga. However, this age peak is not represented by the abundance of exposed crust as in some areas it makes up only a few percent of the watershed where the alluvium was collected. This is the result of the extreme zircon fertility of ~ 1 Ga rocks – an unusually large amount of zircon, and those zircon crystals are often unusually large. Thus there is a considerable bias in the detrital zircon sedimentary record. We have been investigating the causes of the extreme fertility event as well as exploring the utility of a different mineral, a rare earth thorium phosphate called monazite, which forms quite differently from zircon. We have shown that monazite ages reflect much more accurately the actual areal extent of exposed crust. We conclude that in terms of understanding past mountain building events, monazite ‘plays in high tectonic fidelity’
Harnessing the Conformational Dynamics of Outer Membrane Protein G for Biosensing
202/204 Physics
Host: Liviu Movileanu | Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu
The specific detection of proteins, such as cancer biomarkers, viral and bacterial proteins is critical for diseases diagnosis. In an era when the early or immediate detection of viral pathogens is imperative for fighting viral outbreaks, epidemics or terrorist attacks, our ability to respond to these threats depends on the capability of modern biosensors. Pore-forming proteins hold tremendous promise in biotech applications such as DNA sequencing and biosensing. The outer membrane protein G (OmpG) is a monomeric porin which may function as a nonspecific porin for the uptake of oligosaccharides in Escherichia coli. OmpG is composed of 14 β-strands connected by seven flexible loops on the extracellular side and seven short turns on the periplasmic side. The flexible loops move dynamically to create a gating pattern when ionic current passes through the pore. I will discuss our recent work to understand and control the gating of OmpG, and to create a new nanopore sensor for protein detection. Key findings include: (1) the interplay between the loops controls the gating of OmpG; (2)taking advantage of the gating characteristic of the loop’s movement, OmpG pore tethered with a high affinity ligand could distinguish between protein structural homologues. Our results demonstrate the feasibility of directly profiling proteins in real-world samples with minimal or no sample pretreatmentof OmpG, and to create a new nanopore sensor for protein detection. Key findings include: (1) the interplay between the loops controls the gating of OmpG; (2)taking advantage of the gating characteristic of the loop’s movement, OmpG pore tethered with a high affinity ligand could distinguish between protein structural homologues. Our results demonstrate the feasibility of directly profiling proteins in real-world samples with minimal or no sample pretreatment.
Beyond Moore's Law? Seeking Quantum Speedup Through Spin Glasses
202/204 Physics
Host: Alan Middleton | Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu
Can quantum computers indeed meet the promise of doing complex calculations faster than classical computers based on transistor technologies? While the holy grail of a programmable universal quantum computer will probably still take decades to reach, one can already begin to answer this question by testing programmable quantum annealing machines that are currently being built. These machines, such as the D-Wave 2X, use a non-mainstream method known as adiabatic quantum annealing to perform optimization tasks. Unfortunately to date, a conclusive detection of quantum speedup remains elusive. After a general introduction to optimization and its importance in science and technology, I summarize the most recent benchmarking results on quantum optimization machines. In particular, our results show that a careful design of the hardware architecture and benchmark problems is key when building quantum annealing machines. Work done in collaboration with:
Superconducting Qubit Arrays for Quantum Logic Circuits
202/204 Physics
Host: Matt LaHaye | Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu
Quantum computing holds the promise of exploiting superposition and entanglement to surpass conventional digital logic in certain classes of problems. Superconducting qubit circuits at millikelvin temperatures have recently demonstrated key advances such as robust and simple multi-qubit gates, the integration of superconducting qubits into arrays of four or more, and gate fidelities reaching 99%. [1,2,3] The technology has thus matured to the point of integrating multiple qubits to form functional quantum logic circuits. Such circuits will enable quantum error correction via the ‘surface code’ or similar algorithms. In this talk I will discuss a multi-qubit architecture under development at IBM Research, in which two-dimensional arrays of fixed-frequency transmon qubits are coupled via microwave-waveguide buses and microwave-driven two-qubit gates. To scale this architecture into a fully fault-tolerant quantum logic circuit will require advances in the basic physics, engineering and operation of these devices. [4] I will survey these challenges and focus in particular on two issues: 1) how to precisely allocate qubit frequencies in the vicinity of 5 GHz; and 2) how to rapidly read out the qubit state while minimizing losses via the Purcell effect. [5] References [1] J. M. Chow et al, Nature Communications 5, 4015 (2014).
[2] A. D. Corcoles et al, Nature Communications 6, 6979 (2015), 10.1038/ncomms7979.
[3] S. Sheldon et al, arXiv:1603.04821v1 [quant-ph].
[4] J. M. Gambetta et al, arXiv:1510.04375v1 [quant-ph].
[5] N. T. Bronn et al, Appl Phys Lett 107, 172601 (2015).
Thesis Defense - Angular Trapping of a Mirror Using Radiation Pressure
202 Physics
Advisor: Stefan Ballmer
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
Cross Magneto-Mechanical Effects in Amorphous Solids with Magnetic Degrees of Freedom
208 Physics
Host: Jennifer Schwarz | Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu
Metallic glasses with magnetic components exhibit fascinating cross-effects between mechanical and magnetic responses. Magnetostriction and Barkhausen Noise are just a few of these effects. I will describe microscopic models of magnetic glasses and a theory to explain some of the interesting effects that are typical to such systems. I will also talk about glass transition and aging dynamics of such systems.
A Phase Transition in Quantum Einstein Gravity
202 Physics
Host: Simon Catterall, smc@physics.syr.edu | Contact: David Schaich, daschaich@gmail.com
We study the imaginary-time path integral over geometries with spherical topology by summing over approximate Einstein spaces. At positive curvature these consist of an arbitrary number of four-spheres, glued together such that they correspond to `branched-polymer' tree graphs which specify their abundance. At negative curvature, geometries of arbitrary size are constructed by gluing hyperbolic `cups', with an assumed abundance inspired by an earlier proposed large-volume behavior of the partition function in the so-called crumpled phase of the time-space symmetric Euclidean dynamical triangulation model (SDT). Using the semi-classical effective action of the Einstein theory at one-loop order, with a finite UV-cutoff, we construct model partition functions that depend on the four-volume and the gravitational coupling, and study the transition between phases of positive and negative curvature. Qualitative features of the average curvature found in numerical simulations of SDT also appear in this continuum formulation, such as a first-order phase transition with rather strong finite-size effects.
Thesis Defense - Development and Implementation of Efficient Noise Suppression Methods for Emission Computed Tomography
202 Physics
Advisor: Ed Lipson | Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu
Shape Memory Elastomers
202/204 Physics
Host: Mark Bowick | Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu
Shape memory polymers (SMPs) constitute a unique class of polymers that have the ability to fix a temporary shape until they are triggered to return to their original form by an external stimulus. The shape changing mechanism is performed around a transition temperature, often a glass transition temperature (Tg), and relies on vitrification of the chains upon cooling to fix the temporary shape. As a result, SMPs in their fixed state are relatively stiff. A need exists for soft, extensible SMPs with mechanical properties that more closely match those of human tissue. Our group has previously introduced a shape memory elastomeric composite (SMEC) that is rubbery and soft, and yet, has the ability to fix a temporary shape. There, processing approach of imbibing a fiber preform with a silicone precursor was both time-consuming and compositionally restrictive. The work we will present introduces a comparatively simple strategy to prepare SMECs more efficiently and with more control over the composition, thus allowing for adjustment of material properties to meet requirements of a variety of applications. Two polymers are simultaneously electrospun, or dual-spun, forming a composite fiber mat with a controllable composition. This process is shown in the accompanying figure. The two polymers were chosen such that one assists in ‘shape fixing’ and the other in ‘shape recovery’. We will report on the quantitative physical characterization of the new materials, including shape memory properties, also shown in the figure. Finally, very recent work on a reconfigurable shape memory composite will be introduced, with reconfiguration being enabled by anhydride exchange between network chains. We envision that the versatility and simplicity of this fabrication approach will allow for large scale production of shape memory elastomeric composites (SMECs) for a wide range of applications.
The Quest for the Robust Quantum Bit - Implementing Cat-Codes in Superconducting Circuits
202/204 Physics
(refreshments 3:30pm)
Host: Britton Plourde | Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu
Physical systems usually exhibit quantum phenomena, such as state superposition and entanglement, only when they are sufficiently decoupled from a lossy environment. Paradoxically, a specially engineered interaction with the environment can become a resource for the generation and protection of quantum states. Moreover, this notion can be generalized to a manifold of quantum states that consists of all coherent superpositions of multiple stable steady states. In particular, it has now become practically feasible to confine the state of an harmonic oscillator to the quantum manifold spanned by two coherent states of opposite phases. In a recent experiment [1], we have observed a superposition of two such coherent states, also known as a Schrodinger cat state, spontaneously squeeze out of vacuum, before decaying into a classical mixture. The dynamical protection of logical qubits built from Schrodinger cat states is based on an engineered driven-dissipative process in which photon pairs are exchanged rather than single photons. The recent class of experiments in which qubits are encoded using cat states opens a new avenue in quantum information processing with superconducting circuits.
Role of Mechanics in Plant Leaf Vein Morphogenesis
202/204 Physics
Host: Mark Bowick | Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu
Plant leaves and their vascular patterns not only provide some of the most impressive examples of complexity in the nature that surrounds us, but they are also a wonderful system for studying developmental dynamics. In my talk I will focus on the development of leaf primary vein in the growing leaf primordia of Arabadopsis Thaliana, a plant model system. Leaf primary vein is the first in a successive order of branched veins, to emerge in a growing leaf primordia. The development of leaf primary vein starts with very few cells which also synthesize auxin, a growth hormone that regulates both plant and leaf vascular development. The final morphology of primary vein, consists of only a thin strand of distinctively elongated primary vein cells. I will present a cell based model, that describes the formation and morphology of leaf primary vein in early stages of growing leaf primordia. The model captures the interplay between biochemistry and cell mechanics by simulating the tissue growth driven by inter-cellular diffusion of the plant hormone auxin, from auxin synthesizing cells. In close experimental collaboration with a team of plant biologists, we show that the dynamic modulation of cell mechanical properties based on cell auxin concentration can reproduce primary vein pattern, as observed in growing leaf primordia. We further tested our model with experiments in which the wild-type primary vein pattern is affected by inhibiting inter-cellular auxin transport.
Tetraquarks and Pentaquarks - Quark Model Revisited
202/204 Physics
(refreshments 3:30pm)
Host: A. Alan Middleton | Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu
A recent decade has brought new experimental discoveries related to how particles are built from quarks. Syracuse LHCb group has made several important measurements related to tetraquark candidates with hidden charm, and more recently led the data analysis which produced the first credible evidence for pentaquark states. I will present these achievements in historical context, and discuss the present status of spectroscopy of exotic hadrons with heavy quarks.
Scalar Mesons, Gribov Density, and Novel Quark Propagators
202 Physics
Host: Simon Catterall, smc@physics.syr.edu | Contact: David Schaich, daschaich@gmail.com
Two novel methods for calculating quark propagators in lattice QCD will be presented, both of which are inspired from information theory. They aim to extract as much information as possible from the lattice simulations with minimal computational overhead. Observations on the density of Gribov ambiguities in pure Euclidean SU(3) Yang-Mills will be shown, which are in agreement with the Gribov-Zwanziger scenario. Finally, results from 4-point, hadronic (sigma meson) calculations will be presented.
Stevenson Biomaterials Lecture Series
500 Hall of Languages
***NOTE special time*** [Reception to follow]
Host: Cristina Marchetti | Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu
The Stevenson Biomaterials Lecture Series was established in 2007 thanks to the generous support of Trustee Ann McOmber Stevenson (Nursing ‘52) and the late Trustee Emeritus Milton F. Stevenson III (Chemical Engineering ’53). Each semester, the series brings pioneering biomaterials researchers to the Syracuse University campus. Presenters are selected based on their leading roles in biomaterials research, and are asked to speak on their latest endeavors. In addition, Stevenson lecturers visit with faculty and students to exchange ideas, build bridges, and become familiar with the broad range of biomaterials activities at Syracuse University.
ADS Superpotential - a Round Trip to 3 Dimensions
202 Physics
Host: Jay Hubisz, jhubisz@syr.edu | Contact: David Schaich, daschaich@gmail.com
In this talk I will discuss calculation of ADS superpotential in 3 and 4 dimensions in SUSY QCD with F<N flavors. In 4d an explicit instanton calculation exists when $F=N-1$, while in other cases the superpotential can be obtained by decoupling massive flavors. In 3d a similar instanton-monopole calculation of the superpotential exist in a pure SYM theory. I will argue that in a 4d theory compactified on a circle, one could obtain superpotential for all values of F by including multi-monopole contributions to the superpotential. In large and small radius limits one then obtains the exact superpotentials in 3 and 4 dimensions.
A Nonperturbative Regulator for Chiral Gauge Theories
202 Physics
Host: Jay Hubisz, jhubisz@syr.edu | Contact: David Schaich, daschaich@gmail.com
I discuss a new proposal for nonperturbatively defining chiral gauge theories, something that has resisted previous attempts. The proposal is a well defined field theoretic framework that contains mirror fermions with very soft form factors, which allows them to decouple, as well as ordinary fermions with conventional couplings. The construction makes use of an extra dimension, which localizes chiral zeromodes on the boundaries, and a four dimensional gauge field extended into the bulk via classical gradient flow. After explaining the set up, I consider open questions, such as the effects of topological gauge configurations and the viability of these theories, as well as possible exotic phenomenology in the Standard Model lurking at the low energy frontier.
LIGO Observation
202/204 Physics
(refreshments 3:30pm)
Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu
To follow up on the public announcement last week, the LIGO faculty tomorrow will present scientific information about the observation of gravitational waves. You are all invited tomorrow, with refreshments at 3:30 and the presentation starting at 3:45, Thursday, Feb. 18, to learn more about this discovery.
New Possibilities with Top Partial Compositeness
202 Physics
Host: Jay Hubisz, jhubisz@syr.edu | Contact: David Schaich, daschaich@gmail.com
I will review the content of 1501.03818 and 1511.05163. Top partial compositeness is a common feature of composite Higgs models. We study the case where masses for lighter quarks are generated through a different mechanism and we discuss the impact of the experimental constraints on the model, in a specific realization with a pseudo Nambu Goldstone boson Higgs. We show that there is no need for flavor symmetries is the up sector, while in the down sector a certain degree of alignment is required. We finally comment on model building aspects, introducing new physics sector with light top partners candidates, relating their lightness to 't Hooft anomaly matching condition.
The Large-Scale Thermal Stiffening of Graphene Ribbons
202/204 Physics
Host: Mark Bowick | Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu
We use molecular dynamics to study the vibration of a thermally fluctuating 2D elastic membrane clamped at both ends. We identify the eigenmodes from peaks in the frequency domain of the time-dependent height and track the dependence of the eigen-frequency of a given mode on the bending rigidity of the membrane. We find that the effective bending rigidity tends to a constant as the bare bending rigidity vanishes, supporting theoretical arguments that the macroscopic bending rigidity of the membrane as a whole arises from a strong renormalization of the microscopic bending rigidity. Experimental realizations include two-dimensional atomically thin membranes such as graphene and molybdenum disulfide or polymerized membrane ribbons.
EFT of Large Scale Structure, Symmetries and Constraints
202 Physics
Host: Scott Watson, gswatson@syr.edu | Contact: David Schaich, daschaich@gmail.com
I will briefly introduce EFT of large scale structure (LSS) as a systematic perturbative approach to study structure formation. I will identify the symmetries and unique features of the system which determine the structure of EFT expansion. I will show how these symmetries can be used to make non-perturbative predictions about the baryon acoustic peak in the matter correlation function. Finally, I will show how EFT allows us to get unbiased constraints on cosmological parameters such as primordial non-Gaussianity and Neutrino masses from LSS surveys.
Cosmology in Standard Einstein Gravity with Non-Standard Scalar Field Fluids
208 Physics
Host: Scott Watson, gswatson@syr.edu, 315-443-8280
I will discuss cosmological solutions in standard Einstein gravity sourced by non-standard, non-canonical scalar field fluids. With recent experimental data from Planck, BICEP2, and the Keck Array now putting stress on the simplest inflationary models, there is a growing need for alternative early universe scenarios. Examples of such fluids include k-essence, DBI, Galileon fields, Horndeski models and the 'new oscillatory' models recently proposed by Nobel Laureate Wilczek et al. I will focus on the stability of these fluids emphasizing the common occurrence of negative kinetic energy degrees of freedom (ghosts), gradient instabilities (imaginary sound speed), superluminal propagating modes and singularities. Cosmological scenarios I will discuss include K-inflation, Galilean Genesis super-inflation, and the G-bounce model. ---------------------------------------------
Contact Information:
David Schaich, Series Director
daschaich@gmail.com
315-415-3277
The Fluid Boundary - Considering Cell Membranes from a Soft Matter Perspective
202/204 Physics
(refreshments 3:30pm)
Host: Cristina Marchetti
The plasma membrane surrounding cells is composed of lipids and proteins, and is coupled to cytoskeletal fibers and to extracellular matrix. The mixture of lipids that makes up most cell membranes is fluid, forming a liquid film. As a consequence of this fluidity, flow near a membrane can induce a sympathetic flow of lipids and membrane proteins. I will discuss experiments demonstrating this lipid mobility in immobile membranes, and show that fluid flow can be used to advect proteins within lipid bilayers, producing a local concentration gradient. http://www.damtp.cam.ac.uk/people/a.honerkamp-smith/ ---------------------------------------------
Contact Information:
Yudaisy Salomon Sargenton, administration questions
yssargen@syr.edu
315-443-3901
Elasto-capillarity - A New Toolkit for Directed Assembly of Advanced Materials
202/204 Physics
(refreshments 3:30pm)
Host: Cristina Marchetti
The opportunities for guiding assembly using elastic energy stored in soft matter are wide open. The emerging scientific frontiers in this field show an exceptional promise for significant new applications. Since soft materials can be readily reconfigured, there are unplumbed opportunities to make responsive devices including smart windows for energy efficiency, and responsive optical structures. In the other hand, the trapping of colloidal objects at interfaces between immiscible fluids has proven to exhibit incredible abilities to template the arrangement of particles into rich ordered structures. These structures are controlled by lateral forces that compete with capillary forces. However, these interactions are still unexplored when particles are trapped at the interface of an ordered fluid. In this talk, I will present recent progress in understanding the mechanisms that govern interactions between particles at liquid crystal interfaces. I will report how the resulting potential induced by the interplay between elasticity and capillarity could lead to new opportunities for genuine spontaneous self-assembly and create new strategies for making new generation of advanced materials that may find relevance in many applications in the field of energy technology. http://magharbi.wordpress.com/ ---------------------------------------------
Contact Information:
Yudaisy Salomon Sargenton, administration questions
yssargen@syr.edu
315-443-3901
Good Defects or What Confined Liquid Crystals Can Do
Room 202/204
(refreshments 3:30pm)
Host: Cristina Marchetti
Liquid crystals are best known for their use in displays, but their interest extends far beyond. This phase of matter, intermediate between liquid and solid, is composed by anisotropic rod-like molecules which spontaneously align in space. When the molecules cannot achieve a perfect order, they form topological defects, mathematical objects which can be used as physical objects for many purposes. I show two examples of how liquid crystal defects can inspire concepts for new materials. The first example is a bistable system, obtained by confining liquid crystals in a micron-sized cubic scaffold. The device can switch between bright and dark metastable states, thanks to the interaction of the defects with the scaffold. The second example is a self-assembled structure of liquid crystal defects that act as micro-lenses. The structure resembles an insect compound eye, able to focus objects at different distances and sensitive to the polarization of light. Figure 1: Top panel: stable bright and dark states of a display pixel obtained by changing the topological defects. Bottom panel: self-assembled defects around a central pillar. Each defect act as a micro-lens. ---------------------------------------------
Contact Information:
Yudaisy Salomon Sargenton, administration questions
yssargen@syr.edu
315-443-3901
Physics of Cells - Turning Protein Networks into Active Materials
Room 202 and 204 Physics
NOTE: Tuesday Colloquium
Yudaisy Salomon Sargenton, yssargen@syr.edu
Cells are densely packed collections of proteins. By regulating the organization and interaction of these proteins in both space and time, cells turn collections of molecules into networks with various material properties. Here I will discuss how these networks allow cells to generate force and change shape, and the approaches we use to measure their behavior. Finally I will discuss ways in which we can perturb the system using light to spatially control the activity of the component proteins. http://home.uchicago.edu/~poakes/ ---------------------------------------------
Contact Information:
Yudaisy Salomon Sargenton, administration questions
yssargen@syr.edu
315-443-3901
Photoproduction of Scalar Mesons, and Upgrade of the CLAS Electromagnetic Calorimeter at Jefferson Lab
202 Physics
Host: Sheldon Stone
The standard quark model makes no allowance for the existence of gluons outside hadrons; however lattice QCD calculations predict bound states of two or more gluons, called glueballs. According to lattice calculations, the lightest of these experimentally unverified particles is expected to have mass in the range of 1−1.8 GeV and JPC = 0++. Themixing of glueball states with neighbouring meson states complicates their identification. The f0(1500) is one of several candidates for the lightest glueball, whose presence in the K0 sK0 s channel was investigated in photoproduction using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. This was done by studying the reaction, γp → fJp → K0 sK0 s p → 2(π+π−)p using data from the g12 experiment. A moments analysis was performed on this data to characterize the spin properties of the resonance observed at 1.5 GeV. Results from the analysis of this data will be presented. The g12 experiment ran with the CLAS6 detector, so named because of its capability to work with a maximum electron beam energy of 6 GeV. Jefferson Lab has since upgraded its facility to produce electron beam with double that energy. The higher beam energy means that the energy of electrons and photons impinging on the detector will be too high to be contained by the existing CLAS6 electromagnetic calorimeter (EC). Several of the experiments commissioned to be performed using CLAS12 require the accurate detection of neutral pions via their decay into two photons. At the energies of CLAS12, the calorimeter needs to have a very good position resolution in order to be able to detect these two photons and to avoid their labeling as a single photon. It was thus necessary to update the detector sub-system in order to improve its functionality at higher energies. To do this, another calorimeter, the preshower calorimeter (PCAL) is to be placed in front of the EC, the testing and construction of which will be discussed.
Thesis Defense - Vortices and Quasiparticles in Superconducting Microwave Resonators
208 Physics
Advisor: Britton Plourde
Neutral B and Bs Meson Mixing from Lattice QCD
208 Physics
Host: Jack Laiho, jwlaiho@syr.edu, 315-443-0317
Neutral B(s) meson mixing occurs via flavor-changing neutral currents. In the standard model of particle physics this requires quantum fluctuations, or loop diagrams, making the required interactions improbable --- opening the door for the possibility of discernible effects from new physics. There are impressive experimental results in B(s) mixing, with the oscillation frequency between B(s) and anti-B(s) mesons measured with better than sub-percent precision. To better leverage such experimental results in the search for new physics, hadronic contributions must be determined with improved precision. We will discuss an ongoing, nearly complete, lattice QCD calculation of the hadronic matrix elements needed to describe mixing in and beyond the standard model. This work is being carried out by the Fermilab Lattice and MILC collaborations on the MILC Nf=2+1 asqtad gauge field ensembles, including four lattice spacings and numerous light quark masses to permit controlled extrapolations to real-world values. ---------------------------------------------
Contact Information:
David Schaich, Series Director
daschaich@gmail.com
315-415-3277
Thesis Defense - Understanding Disordered Systems Through Numerical Simulation and Algorithm Development
208 Physics
Advisor: Alan Middleton
First-Principles Determination of Hadronic Contributions to the Muon Anomalous Magnetic Moment
202 Physics
Host: Jack Laiho, jwlaiho@syr.edu, 315-443-0317
In order to match the increased precision of the upcoming Fermilab E989 experiment, a more precise determination of hadronic contributions to the muon anomalous magnetic moment is needed. I will present recent progress in a first-principles determination of both the hadronic vacuum polarization and the hadronic light-by-light contribution. ---------------------------------------------
Contact Information:
David Schaich, Series Director
daschaich@gmail.com
315-415-3277
DNA as a Sensor of Hg Nanoparticles
202/204 Physics
Host: Cristina Marchetti
**NOTE: MONDAY SEMINAR** Biomolecules can be used to provide control in organizing technologically important objects into functional nano-materials. ---------------------------------------------
The interaction between biomolecules and inorganic materials is fundamental to these applications. These studies are expected to play role in the design of novel hybrid materials and new sensors for biological and non-biological objects. In our study we have utilized the DNA in two folds. Firstly we useDNA to fabricate self-assembled nanostructures of Hg. Secondly we demonstrate that the DNA can be used as a sensor of Hg nanoparticles. Mercuric nanoparticles (NP) have been fabricated within the DNA scaffold by site specific interactions. The NP get embedded within double helix and exclusively interact with the nucleic acid of DNA, having no influence on the phosphate backbone of DNA. Furthermore, conjugation of Hg NP with DNA exhibits a rectifying transport behavior, with the unreacted DNA displaying the ohmic behavior.
Formation of metal-base complexes as well as the modifications in transport (electrical) properties of DNA can be utilized as sensor of mercury contamination.
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
Freeze-In Dark Matter with Displaced Signatures at Colliders
202 Physics
Host: Jay Hubisz, jhubisz@syr.edu, 315-443-2653
Freeze-in is a general and calculable mechanism for dark matter production in the early universe. Assuming a standard cosmological history, such a framework predicts metastable particles with a lifetime generically too long to observe their decays at colliders. In this talk, I will consider alternative cosmologies with an early matter dominated epoch, and I will show how the observed abundance of dark matter is reproduced only for shorter lifetimes of the metastable particles. Famous realization for such a cosmology are moduli decays in SUSY theories and inflationary reheating. Remarkably, for a large region of the parameter space the decay lengths are in the displaced vertex range and they can be observable at present and future colliders. I will conclude with an example of DFSZ SUSY theories where this framework is realized. ---------------------------------------------
Contact Information:
David Schaich, Series Director
daschaich@gmail.com
315-415-3277
The Vector Portal at the LHC
208 Physics
Host: Jay Hubisz, jhubisz@syr.edu, 315-443-2653
An emerging paradigm in particle physics is the possibility that new matter resides in its own sector — a Dark Sector (DS) — connected to the Standard Model via a portal. In this talk I will focus on a well-motivated example of such a scenario: the vector portal. I will discuss two distinct phases of the theory. In one, matter in the DS is a viable candidate for Dark Matter, giving rise to striking new signals at the LHC. In the other phase of the vector portal, matter in the DS can instead acquire a milli-charge under electromagnetism. I will then discuss a recent proposal to look for milli-charges at the LHC. ---------------------------------------------
Contact Information:
David Schaich, Series Director
daschaich@gmail.com
315-415-3277
TBA
202/204 Physics
Host: Britton Plourde
---------------------------------------------
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
Inside Physical Review Letters
202/204 Physics
Host: Lisa Manning
How do its editors determine which papers to publish in PRL? What guidelines would be helpful to you as an author and a referee? Why should you submit your work to us? How are journals in general and PRL in particular reorienting amid increasing challenges in the landscape of physics publications? I plan to address these and related issues, including a few changes we're implementing, during my presentation. ---------------------------------------------
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
Emergence of Large-Scale Epithelial Mechanics from Cell-Scale Processes - Shaping a Fly Wing
202/204 Physics
Host: Mark Bowick
Epithelia are two-dimensional cellular sheets. They are active visco-elastic materials which gain their mechanical properties from the collective behavior of a large number of cells. Nowadays, we are able to image tissues with up to 10 000 cells in vivo where the behavior of each individual cell can be followed in detail. We want to understand how large-scale tissue deformation and stresses emerge from the behavior of individual cells. ---------------------------------------------
Here, we study this question in the developing Drosophila wing epithelium. We first establish a general geometrical framework that exactly decomposes large-scale tissue deformation into contributions by different kinds of cellular processes. These processes comprise cell shape changes, cell neighbor exchanges (T1 transitions), cell divisions, and cell extrusions (T2 transitions). As the key idea, we introduce a tiling of the cellular network into triangles. This allows us to define the precise contribution of each kind of cellular process to large-scale tissue deformation. Additionally, our rigorous approach reveals subtle effects of correlated cellular motion, which constitute a novel source of tissue deformation.
Based on this geometrical framework, we describe Drosophila wing mechanics using a novel continuum mechanical model. Similar to preceding models, we describe the wing epithelium as visco-elastic. However in addition to that, our observations led us to appreciate novel effects.
We found active cell rearrangements that are oriented on large scales and have an axis orthogonal to the shear stress axis. Furthermore, cell rearrangements did not respond immediately to material stresses, but were rather delayed. These findings are further underpinned using mechanical and genetic perturbations.
With our work, we contribute to an understanding of epithelial deformation and mechanics, linking it to cellular mechanical properties and cell-scale events.
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
Models and Signatures for Neutral Naturalness
202 Physics
Host: Jay Hubisz, jhubisz@syr.edu, 315-443-2653
In the light of the null results in searches for top partners at the 8 TeV LHC, there recently has been an increased interest in models with color neutral top partners. I will review some aspects of neutral naturalness, and discuss some opportunities for progress on the fronts of model building, collider searches and dark matter. (1410.6808, 1411.7393 and in progress with Matt Strassler, Nathaniel Craig, Pietro Longhi, Dean J. Robinson, Yuhsin Tsai and Marat Freytsis.) ---------------------------------------------
Contact Information:
David Schaich, Series Director
daschaich@gmail.com
315-415-3277
Echoes of the Glass Transition in Athermal Soft Spheres
202/204 Physics
Host: Lisa Manning
The glass transition and the athermal jamming transition are both transitions from one disordered state to another marked by a sudden increase in rigidity. Before the onset of rigidity thermal hard spheres and athermal soft spheres both share the same configuration space. Is there a signature of the glass transition in the topology of the allowed configuration space and is this same signature present for athermal spheres? In this talk, I will answer this question by introducing the concept of local rigidity and demonstrate the existence of a pre-jamming phase transition precisely at the glass transition density. http://physics.uoregon.edu/profile/peterm/ ---------------------------------------------
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
The Andersen-Parrinello-Rahman Method Revised into a Scale Bridging Device
202/204 Physics
Host: Matteo Paoluzzi
**NOTE: Wednesday Seminar** Around 35 years ago, Andersen, Parrinello and Rahman had the idea of letting the molecular-dynamics (MD) cell vary its volume (Andersen) and shape (Parrinello & Rahman) with time. The particle velocity was hence decomposed into the sum of a spatially tidy entrainment velocity, parameterized by the cell deformation rate, and a disordered streaming velocity. In order to govern the collective degrees of freedom associated with the cell, the Lagrangian functional was extended in a smart ad-hoc way. Whether the extended Lagrangian could be derived from “first principles” was a question left for further study, as Parrinello & Rahman themselves stated. In reality, since MD practitioners always considered the APR method just as an expedient trick for generating the desired particle statistics, this foundational issue remained latent until recently, when somebody with a background in continuum mechanics (CM) started looking at the APR method from an antipodal point of view. Here the idea is to bring the deforming computational cell to the fore, identifying it with an element - i.e., an infinitesimally small piece - of a continuous medium. Seen in this perspective, the appealing feature of the APR method is that it establishes a natural, explicit coupling between molecular and continuum DOFs. In conventional applications, dynamical quantities work-conjugate to these latter DOFs - namely, stress - are regarded as prescribed: as a matter of fact, Andersen’s original motivation was that of devising a barostat. In the novel multiscale implementation of the method, the stress is a priori unknown: to determine it, CM PDEs have to be solved concurrently with MD ODEs. ---------------------------------------------
Roughly speaking, the solution strategy goes as follows. Imagine considering a material aggregate as either a molecular system or a continuous medium, and wishing to relate the two representations. Assume that the fields entering the continuum description, such as strain and stress, are adequately sampled on an array of positions (think of Gauss points in a finite element model), whose typical spacing H is enormously larger than the average intermolecular distance d. Associate with each of these macroscopic sampling positions an APR cell, whose reference size h is large enough with respect to d in order to allow for a decent sampling of the microscopic molecular states, and still much smaller than H: H >> h >> d (in practice, it is also essential to take full advantage of the fact that, typically, H/h >> h/d). Now, let the molecules in each cell interact directly with each other (and with their h-neighboring images), while being indirectly affected by those in the H-neighboring cells via the collective degrees of freedom of the deforming APR cell, governed by the force balance and compatibility equations of CM (sampled at the H scale). In turn, the elementwise stress-strain relation characterizing the response of the medium arises as an emergent property of MD (computed on the h scale).
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
What is a 6D SCFT?
202 Physics
Host: Scott Watson, gswatson@syr.edu, 315-443-8280
Though long thought not to exist, arguments from string theory strongly indicate the existence of non-trivial interacting conformal field theories in six dimensions. In this talk, I review the evidence that 6D supersymmetric conformal field theories (SCFTs) exist, and then explain how to use the geometry of extra dimensions to classify all such theories. A surprising outcome of this work is that all of these theories admit the structure of a simple generalization of quiver (i.e. moose) diagrams used in the study of lower-dimensional quantum field theories. Time permitting, I will also discuss what we know about these interacting fixed points, and their consequences for understanding quantum field theory in diverse dimensions. ---------------------------------------------
Contact Information:
David Schaich, Series Director
daschaich@gmail.com
315-415-3277
Polarization of Cells and Soft Objects Driven by Mechanical Interactions - Consequences for Migration and Chemotaxis
202/204 Physics
Host: Cristina Marchetti
We study a generic model for the polarization and motility of self-propelled soft objects, biological cells, or biomimetic systems, interacting with a viscous substrate. The active forces generated by the cell on the substrate are modeled by means of oscillating force multipoles at the cell-substrate interface. Symmetry breaking and cell polarization for a range of cell sizes naturally “emerge” from long range mechanical interactions between oscillating units, mediated both by the intracellular medium and the substrate. However, the harnessing of cell polarization for motility requires substrate-mediated interactions. Motility can be optimized by adapting the oscillation frequency to the relaxation time of the system or when the substrate and cell viscosities match. Cellular noise can destroy mechanical coordination between force-generating elements within the cell, resulting in sudden changes of polarization. The persistence of the cell’s motion is found to depend on the cell size and the substrate viscosity. Within such a model, chemotactic guidance of cell motion is obtained by directionally modulating the persistence of motion, rather than by modulating the instantaneous cell velocity, in a way that resembles the run and tumble chemotaxis of bacteria. ---------------------------------------------
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
CUWiP Informational Session
202/204 Physics
(refreshments 3:30pm) ---------------------------------------------
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
Galilean Creation of the Inflationary Universe
208 Physics
Host: Scott Watson, gswatson@syr.edu, 315-443-8280
It has been pointed out that the null energy condition can be violated stably in some non-canonical scalar-field theories. This allows us to consider the Galilean Genesis scenario in which the universe starts expanding from Minkowski spacetime and hence is free from the initial singularity. We use this scenario to study the early-time completion of inflation, pushing forward the recent idea of Pirtskhalava et al. We present a generic form of the Lagrangian governing the background and perturbation dynamics in the Genesis phase, the subsequent inflationary phase, and the graceful exit from inflation, as opposed to employing the effective field theory approach. Our Lagrangian belongs to a more general class of scalar-tensor theories than the Horndeski theory and Gleyzes-Langlois-Piazza-Vernizzi generalization, but still has the same number of the propagating degrees of freedom, and thus can avoid Ostrogradski instabilities. We investigate the generation and evolution of primordial perturbations in this scenario and show that one can indeed construct a stable model of inflation preceded by (generalized) Galilean Genesis. ---------------------------------------------
Contact Information:
David Schaich, Series Director
daschaich@gmail.com
315-415-3277
Microswimmer — From Swimming Bacteria to Collective Behaviours of Active Brownian Particles
202/204 Physics
Host: Cristina Marchetti
Locomotion is a major achievement of biological evolution. Microorganisms, such as bacteria, algae, and sperm cells are equipped with flagella and are able to exploit drag for their propulsion. Two prominent swimming mechanisms are rotating helical flagella, exploited by many bacteria, and snake-like or whip-like motion of eukaryotic flagella, utilized by sperm and algae. Thereby, hydrodynamic interactions play a major role in the swimming motion. ---------------------------------------------
In assemblies of motile microorganisms, cooperativity plays a major role as they exhibit highly organized movements with remarkable large-scale patterns such as networks, complex vortices, or swarms. To unravel the emergent behaviors often simplified models such as active Brownian particles (ABPs) are considered. The generic approaches provide valuable insight into the non-equilibrium statistical aspects of active matter.
In the talk, theoretical and computer simulation results will be presented for the swimming behavior of E. coli bacteria, both in bulk and at surfaces. Moreover, the cooperative dynamics of ABPs will be discussed and a link will be established to the non-equilibrium pressure equation of state.
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
Capillary Fracture
202/204 Physics
Host: Cristina Marchetti
I will describe the initiation and growth of fractures in gels close to their solid-liquid transition, caused by the placement of a fluid droplet on the surface. In experiments, we observe that channel fractures form at the surface of the gel, driven by fluid propagating away from the central droplet. The fractures take the form of starburst-like cracks, with their initiation governed by two processes. First, surface-tension forces exerted by the droplet deform the gel substrate and break azimuthal symmetry. We model the substrate as an incompressible, linear-elastic solid and characterize the elastic response to provide a prediction for the number of fracture arms as a function of material properties and geometric parameters. Second, a thermally-activated process initiates a starburst-shaped collection of fractures corresponding to this strain-patterning. Once initiated, the fractures grow with a universal power law L=t^3/4, with the speed limited by the transport of an inviscid fluid into the fracture tip. ---------------------------------------------
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
Temperature-like Variables in Granular Materials
202/204 Physics
Host: Jen Schwarz
(refreshments 3:30pm) Statistical mechanics has provided a powerful tool for understanding the thermodynamics of materials. Because granular materials exhibit reproducible statistical distributions which depend in simple ways on macroscopic parameters such as volume and pressure, it is tempting to create a statistical mechanics of athermal materials. I will describe a suite of experiments on two-dimensional granular materials which investigate to what extent these ideas are meaningful. For example, under agitated conditions, we measure both bulk and particle-scale dynamics, and find a number of thermal-like behaviors including diffusive dynamics, a granular Boyle's Law with a van der Waals-like equation of state, and energy equipartition for rotational and translational degrees of freedom. However, the scarcity of free volume within a granular material provides a crucial control on the dynamics, and each of the above thermal-like behaviors is accompanied by interesting caveats. In an apparatus designed to generate a large number of static configurations, we test whether or not various temperature-like variables are able to equilibrate between a subsystem and a bath. We find that while a volume-based temperature known as "compactivity" fails to equilibrate, a stress-based temperature succeeds. This points to the importance of interparticle forces in controlling the mechanics of granular materials. ---------------------------------------------
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
Walking and Conformal Dynamics in Many-Flavor QCD on the Lattice
202 Physics
Host: Simon Catterall, smc@physics.syr.edu, 315-443-5978
In the search for a realistic walking technicolor model, QCD with many flavors, in particular with Nf=8, is an attractive candidate, which has been found to have a composite scalar as light as pion. Based on lattice simulations with the HISQ action, I will present our lattice results of the scaling properties of various hadron spectra, including the (pseudo)scalar, vector, and baryon channels in comparison with Nf=12 QCD, which is most likely in the conformal phase. Some implications for dark matter and collider phenomenology in the technicolor model will be also discussed. ---------------------------------------------
Contact Information:
David Schaich, Series Director
daschaich@gmail.com
315-415-3277
The Geometry and Mechanics of Growth and Defects
202/204 Physics
Host: Mark Bowick
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
Hard Problems in Soft Matter - How We Think, Eat, and Protect Ourselves
202/204 Physics
(refreshments 3:30pm) Soft matter is the study of matter that easily deforms via thermal fluctuations and/or external and/or internal driving. Given this rather inclusive definition, a vast range of systems falls under the soft matter purview, including brain tissue, cell membranes, biopolymers, and granular materials. I will address (1) how the brain gets its folds to ultimately better understand the interplay between structure and function of the brain, (2) how cells engulf extracellular proteins, i.e. how we eat, with "we" in the collective sense of living systems, and (3) how we (cells and humans) build disordered frameworks with structural integrity (rigidity) to protect ourselves from the "elements". ---------------------------------------------
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
***BMCE Seminar***
105 Link Hall
---------------------------------------------
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
Leveraging Computational Social Science to Address Grand Societal Challenges
Strasser Room (220 Eggers Hall)
Kameshwar C. Wali Lecture in the Sciences and Humanities
The increased access to big data about social phenomena in general, and network data in particular, has been a windfall for social scientists. But these exciting opportunities must be accompanied with careful reflection on how big data can motivate new theories and methods. Using examples of his research in the area of networks, Contractor will argue that Computational Social Science serves as the foundation to unleash the intellectual insights locked in big data. More importantly, he will illustrate how these insights offer social scientists in general, and social network scholars in particular, an unprecedented opportunity to engage more actively in monitoring, anticipating and designing interventions to address grand societal challenges. ---------------------------------------------
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
The Big Science of Little Neutrinos
202/204 Physics
(refreshments 3:30pm) Experimental studies of neutrinos are notoriously challenging due to the feebleness of their interactions with matter, so it may seem counterintuitive to suggest these “little neutral ones” could have played a central role in the development of our universe to its current matter-dominated state. This talk will provide an overview of the interesting physics questions associated with neutrinos, and will give an outlook on the global program to build bigger and better detectors to uncover the answers to these questions. ---------------------------------------------
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
***BMCE Seminar***
105 Link Hall
---------------------------------------------
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
Mechanical Quantum Systems
202/204 Physics
(refreshments 3:30pm) The field of mechanical quantum systems has made great strides in recent years developing the technology to begin eliciting and studying quantum behavior of structures that are normally well described by classical laws of physics. While the full potential of the field is yet unknown, it is thought that these mechanical systems could have important applications serving as elements in quantum computing and communication architectures, and could also enable explorations of fundamental topics in quantum mechanics like the quantum-to-classical divide. In my talk, I will first give an overview of this growing field. Then I will highlight ongoing work in my group to develop a particular type of mechanical quantum system - a quantum electromechanical system - that is composed of integrated superconducting circuity and nanomechanical elements and could prove to be an important test-bed for the study of quantum mechanics in new macroscopic limits. ---------------------------------------------
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
Catching Gravitational Waves
202/204 Physics
(refreshments 3:30pm) In 1916 Einstein first predicted the existence of gravitational waves. But due to their intrinsic weakness it took almost a century of technological progress to build a receiver capable of detecting gravitational waves. This receiver, a set of laser interferometers with 4km arm length able to detect distance variations as small as one 100'000th the size of an atomic nucleus, is the Advanced Laser Interferometer Gravitational-wave Observatory. It will start its first observation run this fall. Advanced LIGO is designed to observe gravitational waves from the merger of binary neutron stars and black holes, providing the first direct measurements of strong field gravity. I will discuss the current status and sensitivity of the Advanced LIGO detectors, and I will explore options for short and long term upgrades. In particular, I will focus on the two most limiting noise sources: quantum noise of the light and thermal noise, highlighting some of the work done in my group. For lowering the quantum noise, the use of non-classical light looks most promising, and we are focusing on integrating this technology to Advanced LIGO. For mitigating thermal noise several approaches are possible. The most far reaching one will lead us into the design of future gravitational wave detectors, capable of observing mergers of binary neutron stars at red shifts above z=7. ---------------------------------------------
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
***BMCE Seminar***
105 Link Hall
---------------------------------------------
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
The State of the Universe
Room 202/204 Physics
(refreshments 3:30pm) Cosmological observations provide overwhelming evidence that our universe is almost entirely comprised of dark energy and dark matter, both of which have no theoretical explanation within the standard model of particle physics. The former is responsible for a current period of cosmic acceleration, much like that which occurred in the earliest moments of the universe. The early period of cosmic acceleration, known as inflation, was vital in providing the primordial seeds from which galaxies and clusters formed, whereas the late time acceleration could eventually lead to the vanishing of most structure in the universe. The driving force behind cosmic acceleration, as well as dark matter, still remains elusive from the point of view of a microscopic theory. Combined with fundamental questions, such as the origin of particle mass and how electroweak symmetry is broken, these conundrums require physics beyond the standard model. In this talk I will review both the theoretical and observational status of these issues with an emphasis on the excitement surrounding current and upcoming experiments. ---------------------------------------------
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
Department Welcome Reception (Tuesday)
Room 202/204 Physics
Hosted by the Physics Department
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
Thesis Defense - Measurement of the Form Factor Shape for the Semileptonic Decay Lb → LcMuNu
Room 202 Physics
Advisor: Marina Artuso
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
Thesis Defense - The Effects of Spinning Neutron Stars and Hlack Holes on Gravitational-Wave Searches for Binary Neutron Star and Neutron Star - Black Hole Mergers
Room 208 Physics
Advisor: Duncan Brown
Thesis Defense - Modulation of Charged Biomimetic Membrane by Bivalent Ions
Room 202 Physics
Advisor: Martin Forstner
Thesis Defense - Beyond Standard Model Physics Under the Ground and in the Sky
Room 202 Physics
Advisor: Jay Hubisz
Thesis Defense - Collective Phenomena in Active Systems
Room 202 Physics
Advisor: M. Cristina Marchetti
Contact Information:
Penny Davis, administration questions
shdavis@syr.edu
315-443-5960
How do Molecules Form in Star-forming Regions?
208 Physics
Host: Gianfranco Vidali
More than 150 different gas phase molecules and around 20 molecular species on the grain surface have been detected in various regions of the Interstellar Medium (ISM). Many of these molecules are organic, and therefore important astro-biologically. These molecules range in complexity from diatomic H2 to a 15-atom linear nitrile, HC13N. I will discuss how these molecules are formed in a variety of astrophysical sources, with an emphasis on their formation in the star forming regions. Numerical techniques we developed to study the formation of these molecules include the rate equation method, as well as several more detailed stochastic methods, based upon either the direct solution of the master equation or a Monte Carlo realization of the problem. In this talk, I will present results obtained for diffuse clouds and dust grain mantle compositions, and will discuss their dependence on various physical parameters associated with a star forming region.
Phase Transitions and Pattern Formation in Myxococcus Xanthus
202/204 Physics
Host: Cristina Marchetti