Bootstrapping the Stress-Energy Tensor
208 Physics Bldg.
Host: Judah Unmuth-Yockey/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
Fire! Fire! (Einstein’s) Hair on Fire! The Equivalence Principle and Quantum Mechanics; Are They Compatible? by Carl Rosenzweig
Room: 202/204 Physics Bldg.
Contact: Yudaisy Salomon Sargenton, 315-443-5960
The Equivalence Principle is one of the physical foundations of General Relativity. Quantum Mechanics is the most successful and pervasive theory in physics. Black Holes are the setting for gedanken experiments exploring the relationship between these two pillars of modern physics. In recent years Black Hole thought experiments suggested the existence of a firewall surrounding Black Holes. This ring of fire would fry to a crisp any physicist trying to validate the equivalence principle. Unless Quantum Mechanics was wrong….. or something else ????
Tensor formulations for spin and gauge models on the lattice
233 Physics Bldg.
Contact: Yudaisy Salomón Sargentón, 315-443-5960
I will introduce tensor formulations for spin and gauge models on the lattice, using methods from usual duality transformations. This formulation of models changes the degrees of freedom to be integer fields on the interaction surfaces of the original model. I will also discuss some exact blocking methods with this formulation, as well as some approximate blocking methods, and some applications where this formulation has been advantagous.
Confining colloids: From dynamic artificial cells to luminescent nanodiamond sensors - by Viva Horowitz
Rooms 202/204
Host: Lisa Manning | Contact: David Yllanes, dyllanes@syr.edu
Watching nano- and microscale particles in confined environments can reveal new physics, whether we create a dynamic system that mimics cellular motion or use the quantum spin of nanodiamonds to explore a magnetic environment. In the first part of this talk, we’ll explore the possibilities of using self-propelled particles to create a super-diffusive system that beats Brownian motion, much like the interior of cells. We’ll discuss how to investigate the motion of these particles using holography and other optical techniques, and see how these particles can be encapsulated in lipid vesicles or in droplets. The dynamics and transport processes of this artificial cytoplasm may prove necessary to sustain gene expression, growth, and reproduction in future artificial cells. In the second part, we’ll explore how nitrogen-vacancy color centers embedded in nanoparticle diamonds have electronic quantum spin states that are sensitive to magnetic fields via electron spin resonance. When we pick up these nanodiamond probes using optical tweezers, we can measure and map the magnetic environment despite the motion and random orientation of nanodiamonds levitated by the laser beam. However, challenges remain: these spin states are sensitive to impurities in the diamond crystal and surroundings. We need to find the best diamond particles for spin-based magnetic, electric, and thermal sensing in fluidic environments and biophysical systems. Toward this end, we are building a microfluidic device to sort nanodiamonds according to their optical properties.
Eye patches: the evolution of novel soft matter by Alison Sweeney
Room: 202/204 Physics Bldg.
Host: Prof. Edward Lipson / Contact: Yudaisy Salomón Sargentón, 315-443-5960
Life on Earth constitutes the most sophisticated iterations in the known universe of what physicists classify as soft matter. Research in my group focuses on learning the physical rules of soft matter self-assembly phenomena via the evolutionary processes by which they arose over Earth’s history. In this view of life as soft matter, evolution, with its own formal rules and algorithms, governs the appearance and diversification of novel forms of soft matter. The field of soft matter was until very recently restricted to analytical consideration of simpler systems like isotropically interacting colloids and cross-linked polymers such as rubber. Our approach allows us to understand soft materials in a nuanced manner that would be inaccessible from more top-down analytical approaches. In this talk, I will present the most detailed test case of this perspective to date: the evolutionary appearance of spherical, gradient-index lenses in squids. This complex optical material, first described in theory by Maxwell in 1854, emerges from 5-nm spheroidal proteins via patchy colloidal physics. The lens requires stable, transparent materials throughout the span of packing fractions (from near zero to near one); accordingly, the lens proteins exploit the entire patchy colloidal phase space, and our work is the first demonstration of many of these colloidal organizations in nature. The self-assembling squid proteins exhibit structural features that have also been predicted by self-assembly theories but not yet realized in experiments, such that the evolved system may provide helpful insight to engineers designing systems at similar lengthscales. Conceptually related projects such as the structure and function of quasi-ordered optics for camouflage of midwater squid eyes will also be discussed.
Loop equations and bootstrap methods in lattice gauge theory by Luis Martin Kruczenski
202 Physics Bldg.
Host: Simon Catterall/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
In principle, the loop equation allows, especially in the large-N limit, the formulation of a gauge theory purely in terms of Wilson loops. This is particularly so in lattice gauge theories where there is a countable number of loops. In this talk we argue that the loop equation does not uniquely determine the Wilson loops unless it is supplemented by a certain positivity condition. Imposing that a certain matrix built out of expectation values of Wilson loops is positive definite gives a well defined problem that can be approached using semi-definite programming, a well-developed numerical technique. Further, we discuss a certain entropy associated with this matrix and other related developments. Based on arXiv:1612.08140 and work in progress.
The Physics of Cancer Lecture by Prof. M. Lisa Manning
Room: 202/204 Physics Bldg.
As part of Orange Central events, Physics professor M. Lisa Manning, Ph.D., will discuss recent work that may help explain when and why cells are able to leave tumors. This research is generating new ideas about how to use cell mechanics and cell shape to quantify tumor invasiveness, which will help patients get the best treatments for their disease.
Event Cost: No charge
Fine-Tuning Constraints on Stellar Operations by Prof. Fred Adams
208 Physics Bldg.
Host: Prof. Scott Watson / Contact: Yudaisy Salomón Sargentón, 315-443-5960
Motivated by the possible existence of other universes, with different values for the fundamental constants, this talk considers stars and stellar structure with different values for the fundamental constants of nature. Focusing on the fine structure and gravitational constants, we first enforce the following constraints: [A] long-lived stable nuclear burning stars exist, [B] planetary surfaces are hot enough to support chemistry, [C] stellar lifetimes are long enough to allow biological evolution, [D] planets are massive enough to maintain atmospheres, [E] planets are small enough to remain non-degenerate, [F] planets are massive enough to support complex biospheres, [G] planets are less massive than stars, and [H] stars are less massive than galaxies. The parameter space that satisfies these constraints is relatively large: viable universes can exist when the structure constants vary by several orders of magnitude. Next we consider a number of other fine-tuning issues, including the triple alpha fine-tuning problem for carbon production, nucleosynthesis in universes without stable deuterium, and structure formation in universes with varying amplitudes for the primordial density fluctuations. In all of these scenarios, the basic parameters of physics and cosmology can vary over wide ranges and still allow the universe to operate.
Quantum Simulation of Quantum Chemistry by Peter Love
Room: 202/204 Physics Bldg.
Host: Prof. Britton Plourde/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
Quantum simulation proposes to use future quantum computers to calculate properties of quantum systems. In the context of chemistry, the target is the electronic structure problem: determination of the electronic energy given the nuclear coordinates of a molecule. Since 2006 we have been studying quantum approaches to quantum chemical problems, and such approaches must face the challenges of high, but fixed, precision requirements, and fermion antisymmetry. I will describe several algorithmic developments in this area including improvements upon the Jordan Wigner transformation, alternatives to phase estimation, adiabatic quantum computing approaches to the electronic structure problem, methods based on sparse Hamiltonian simulation techniques and the potential for experiments realizing these algorithms in the near future.
The QCD equation of state at finite temperature and density
Room: 202 Physics Bldg.
Host: Judah Unmuth- Yockey, Contact: Yudaisy Salomon Sargenton, 315-443-3901
TBD by Chandraleckha Singh and Genaro Zavala
Room: 202/204 Physics Bldg.
Organizer: Samuel Sampere, 315-443-5999, smsamper@syr.edu
6th Annual Regional AAPT Meeting
Syracuse University Department of Physics
Organizer: Samuel Sampere, 315-443-5999, smsamper@syr.edu
NJAAPT
AAPT-NEW ENGLAND
FRIDAY
4:00 – 6:00 REGISTRATION
6:30 – 8:30 COCKTAILS AND DINNER IN HEROY LOBBY ($20)
PLENARY - BETH CUNNINGHAM EXECUTIVE OFFICER AAPT
8:45 – 9:45 DEMO SHOW
STOLKIN AUDITORIUM (PHYSICS BUILDING) 8:45 ~ 9:30
SATURDAY
7:30 – 8:15 REGISTRATION
8:30 – 8:50 BRAD GEARHART – SHADOWGRAMS USING YOUR IPAD
8:50 -9:10 ANNE HUNTRESS – PRINTING WITH 3D PENS
9:15 – 9:45 INVITED TALK #1 (CHANDRALEKHA SINGH OR GENARO ZAVALA)
9:50 – 10:20 INVITED TALK #2 – RYAN FISHER – THE LATEST LIGO NEWS
10:20 – 10:35 MORNING BREAK
10:40 – 11:10 INVITED TALK #3 - (CHANDRALEKHA SINGH OR GENARO ZAVALA)
11:10 – 11:30 QUESTIONS FOR MORNING SPEAKERS
11:30 – 1:00 LUNCH AND POSTERS
WORKSHOPS
1:00 – 4:00 PTRA WORKSHOP, FUN AND ENGAGING LABS – STEVE HENNING (FEE: $30)
1:00 – 3:00 BICYCLE POWER WORKSHOP – SHAWN REEVES
1:00 – 2:00 3D PRINTING USING PENS – ANNE HUNTRESS
TALKS
1:00 – 1:30 JOSEPH RIBAUDO – HOW KILLER BLACK HOLES SAVED ASTRONOMY
1:30 – 2:00 CHARLES HOLBROW – ARISTARCHUS’S DISTANCES TO THE MOON AND SUN: MYTH, MYSTERY, OR
MISTAKE?
2:00 – 2:20 SAM SAMPERE AND BRAD GEARHART – ULTRASONIC LEVITATION OF STYROFOAM BEADS AND SHADOWGRAM
IMAGING
2:20 – 2:30 CONCLUDING REMARKS (WORKSHOP ATTENDEES RETURN TO WORKSHOPS)
Probing Fundamental Physics with the Early Universe by Will Kinney
Room: 202/204 Physics Bldg.
Contact: Yudaisy Salomón Sargentón, 315-443-5960
The current revolution in high-precision cosmology is revealing amazing detail about the structure and evolution of the universe, and provides a unique laboratory to study questions in fundamental physics inaccessible to traditional particle physics methods using colliders such as LHC. For example, the physics responsible for cosmological inflation is likely to operate at an energy scale comparable to that of Grand Unification. Since inflation leaves behind observable relics, in particular primordial cosmological perturbations, the inflationary universe provides us with a "microscope'' of tremendous power. In the last decade, it has been realized that inflation may even enable us to probe physics at the very highest energies, where quantum gravity becomes important. The first observational signatures of string theory (or some other theory of quantum gravity) may well come from cosmology. In this colloquium, I introduce inflation as a probe of fundamental physics, and discuss current status and future prospects.
Glueball masses from SU(3) Matrix Model by Sachin Vaiyda
202 Physics Bldg.
Host: Simon Catterall/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
We present variational estimates for the low-lying energies of a simple matrix model that approximates SU(3) Yang-Mills theory on a three-sphere of radius R. By fixing the ground state energy, we obtain the (integrated) renormalization group (RG) equation for the Yang-Mills coupling g as a function of R. This RG equation allows us to estimate the masses of other glueball states, which we find to be in excellent agreement with lattice simulations.
Emerging insights into directed assemble: taking examples from nature to design synthetic processes by Juan de Pablo (BMCE Distinguished Lecture)
414 Bowne Hall
Contact: David Yllanes, dyllanes@syr.edu
There is considerable interest in controlling the assembly of polymeric material in order to create highly ordered materials for applications. Such materials are often trapped in metastable, nonequilibrium states, and the processes through which they assemble become an important aspect of the materials design strategy. An example is provided by di-block copolymer directed self-assembly, where a decade of work has shown that, through careful choice of process variables, it is possible to create ordered structures whose degree of perfection meets the constraints of commercial semiconductor manufacturing. As impactful as that work has been, it has focused on relatively simple materials – neutral polymers, consisting of two or at most three blocks. Furthermore, the samples that have been produced have been limited to relatively thin films, and the assembly has been carried out on ideal, two-dimensional substrates. The question that arises now is whether one can translate those achievements to polymeric materials having a richer sequence, to monomers that include charges, to three-dimensional substrates, or to active systems that are in a permanent non-equilibrium state. This presentation will review recent work from our group and others that explains how directed assembly of polymeric materials and liquid crystals can be used to create functional thin films for applications in separations, nanofabrication, sensors and photonic materials. Building on discoveries from the biophysics literature, I will then discuss how nature has evolved to direct the assembly of nucleic acids into intricate, fully three-dimensional macroscopic functional materials that are not only active, but also responsive to external cues. We will discuss how principles from polymer physics serve to explain those assemblies, and how one might design a new generation of synthetic systems that incorporate bio-inspired designs.
Physics Slam
Room: 202/204 Physics Bldg.
Organizer: Prof. Steven Blusk, Contact: Yudaisy Salomón Sargentón, 315-443-5960
This colloquium will be devoted to presentations specifically aimed at the undergraduate level. There will be 4 speakers, with the titles presented below:
Soft, Structured, Living Materials by Jesse Silverberg
Rooms 202/204
Host: Cristina Marchetti | Contact: David Yllanes, dyllanes@syr.edu
The central narrative of contemporary biology is that DNA encodes all relevant information for an organism’s function and form. While this genotype-to-phenotype framing is appealing for its reductionist simplicity, it has a substantial problem. Between nanometer-scale DNA and organismal-scale phenotype sits a gap of 5 to 9 orders of magnitude in length. This gap covers everything from active protein diffusion, and macromolecular self-assembly, to biopolymer networks and pattern forming mechanical instabilities. In other words, the story of how organisms get their function and form starts with genes, but rapidly transitions to the language of soft matter physics as we examine larger and longer length scales.
In this talk, I’ll address technological challenges and solutions for studying multiscale biophysics in an experimental setting. Along the way, I will discuss how cm-scale cartilage tissue achieves its remarkable mechanical properties through biopolymer self-organization, and how advances in big data and cloud computing can be leveraged for visualizing this nm-scale structure. I will continue to develop the theme of multiscale biophysics in the context of cell-cell fusion, a remarkably common yet mysterious processes in which individual cells fuse together to increase their size ~1,000-fold while decreasing metabolic costs by ~75%. I will also briefly touch on current work studying embryonic morphogenesis where gradients in cell growth lead to the geometric nonlinearities driving epidermal pattern formation. The physics of phase transitions, instabilities, and networks will become reoccurring themes that appear in surprising and unexpected ways as we work to close the genotype-to-phenotype gap.
Lattice Quantum Gravity and Asymptotic Safety by Jack Laiho
Room: 202/204 Physics Bldg.
Contact: Yudaisy Salomón Sargentón, 315-443-5960
We discuss the approach of lattice quantum gravity to formulating a quantum theory of gravity and how this fits into Weinberg's asymptotic safety scenario. We present results that lattice gravity might provide a sensible definition of quantum gravity that resolves some of the long-standing problems with formulating such a theory.
Physics Department Fall Picnic
Green Lakes’ Reserve Shelter
Contact: Yudaisy Salomón Sargentón, 315-443-5960
Please join us on Sunday, September 10th, 2017 for the Physics Department Fall Picnic at Green Lakes’ Reserve Shelter. There will be food, there will be games, there will be fun! *Please note that cleanup is starts at 3 pm. Guests are welcome to stay longer if they so wish. Note that this it is a 'carry in carry out park.'
APS Bridge Program: Changing the Face of Physics Graduate Education by Theodore Hodapp
Room: 202/204 Physics Bldg.
Host: Prof. Gianfranco Vidali / Contact: Yudaisy Salomón Sargentón, 315-443-5960
In nearly every science, math, and engineering field there is a significant falloff in participation by underrepresented minority (URM) students who fail to make the transition between undergraduate and graduate studies. The American Physical Society (APS) has realized that a professional society can erase this gap by acting as a national recruiter of URM physics students and connecting these individuals with graduate programs that are eager to a) attract motivated students to their program, b) increase domestic student participation, and c) improve the diversity of their program. Now in its fifth year the APS has placed enough students into graduate programs nationwide to eliminate this achievement gap. The program has low costs, is popular among graduate programs, and has inspired other departments to adopt practices that improve graduate admissions and student retention. This presentation will review project activities, present data that demonstrate effectiveness, discuss future actions, and review related efforts that inform and support activities that increase diversity within physics. This material is based upon work supported in part by the National Science Foundation under Grant No. (NSF-1143070).
Engineering Pathways Across Biological Barriers by Shikha Nangia (BMCE Seminar)
414 Bowne Hall
Contact: David Yllanes, dyllanes@syr.edu
The process of engineering pathways across biological barriers is entering a new era with the rapid advancement of computational resources. My research group focuses on developing multiscale simulation methods to elucidate the interfacial phenomena associated with biological barriers that play a role in life-threatening diseases such as Alzheimer’s disease, cancer, and chronic infections. The goal is to influence the experimentally dominated research field by providing mechanistic, structural, and molecular insights into the barrier functions that were computationally unattainable prior to our work. In past five years, we have made breakthroughs in each of three research domains—elucidated the molecular architecture of the blood-brain barrier and developed strategies to enhance the barrier’s permeability for treatment of the neurodegenerative diseases; developed telodendrimer based nanocarriers for efficient delivery of approved anticancer drugs for treatment of solid tumors; and designed an online computational platform to screen libraries of small molecules for their permeability across bacterial membranes and determine their use as antibiotics for treatment of chronic infections. All three research domains have ties with experimental groups to ensure the validity of our research findings. In my talk, I will elaborate on our computational methods, present the key results, and provide a perspective on the long-term research goals of the group.
Physics Department Welcome Reception
Room: 202/204 Physics Bldg.
Contact: Yudaisy Salomón Sargentón, 315-443-5960
Adventure Course and Team building activity
The Syracuse University Outdoor Education Center and Challenge Course. 600 Skytop Road, South Campus
Contact: Patty Whitmore, 315-443-5958
The Physics Department invites all new graduate students to participate on this fun, team building activity. See the Department orientation schedule for more details.
Eclipse Party
Stolkin Auditorium and the Quad
Host: Sam Sampere. Contact: Yudaisy Salomon Sargenton, 315-443-3901
There is going to be a partial solar eclipse visible from Syracuse on Monday August 21. To accentuate this celestial event and promote greater science understanding, the Physics Department will be hosting an Eclipse Party. We will start with live streaming of the eclipse starting at 11 am in Stolkin Auditorium (located in the Physics Building). Prof. Carl Rosenzweig will give a short talk on celestial mechanics and why eclipses are not more frequently seen. Following the talk will come the actual eclipse, and we invite all attendees to join us on the quad right outside the Physics Building. We will have two telescopes focused on the sun for up close and personal viewing of this rare occasion. We will also have a limited amount of solar viewing glasses, so you can witness the event without damaging your eyes. Never look at the sun without proper eye protection, even during a partial eclipse.
Annual Pancake Breakfast
Room: 202/204 Physics Bldg.
Host: Sam Sampere. Contact: Patty Whitmore, 315-443-5958
The Physics Department is hosting the Annual Pancake Breakfast on Monday, August 21, 2017. All graduate students, faculty and staff are invited. Please come and meet our new graduate students in a fun, relaxed atmosphere. A delicious hot breakfast will be served.
Quarknet 2017
8/21 Room 104N, 8/22 and 8/23 Room 208 Physics Bldg.
Host: Prof. Steven Blusk/ Contact: Yudaisy Salomón Sargentón, 315-443-5960
Ten high school teachers from local area high schools will participate in an event sponsored by the experimental high energy physics group. Teachers will be setting up a cosmic ray detector to measure and analyze the cosmic ray flux before, during and after the solar eclipse. Teachers will also engage in an activity using data from the CMS experiment at CERN, where they study decays of a massive particle called the Z0 boson. The activities will be guided by and supplemented with presentations by Profs. Blusk and Rudolph.” For details about the event, click here
Comprehensive exam
Room: 202/204 Physics Bldg.
Contact: Patty Whitmore, 315-443-5958
Saturday, August 19 and Sunday, August 20; Comprehensive Exam Part I - Saturday; Part II - Sunday There are two examinations given in August. All new graduate students must take the comprehensive examination. You may choose to attempt the qualifying examination. - email pawhitmo@syr.edu if you would like to take it. Second year students take the qualifying examination. Bot examinations have two parts: one on Saturday, one on Sunday).
2:00 p.m. - 4:00 p.m.
ALL INCOMING STUDENTS
Qualifying Exam
Room: 202/204 Physics Bldg.
Contact: Patty Whitmore, 315-443-5958
Saturday, August 19 and Sunday, August 20; Qualifying Exam There are two examinations given in August. All new graduate students must take the comprehensive examination. You may choose to attempt the qualifying examination. - email pawhitmo@syr.edu if you would like to take it. Second year students take the qualifying examination. Both examinations have two parts: one on Saturday, one on Sunday).
9:00 a.m. - 12:00 p.m.
Thesis Defense by Kazage J Christophe Utuje
202 Physics Bldg.
Advisor: Prof. Cristina Marchetti / Contact: Yudaisy Salomón Sargentón, 315-443-5960
Thesis Defense by Prashant Mishra
202 Physics Bldg.
Advisor: Prof. Cristina Marchetti / Contact: Yudaisy Salomón Sargentón, 315-443-5960
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.