revised
PHYSICS
COLLOQUIA: FALL 2005/SPRING 2006
Series
Director : Cristian Armendariz-Picon
Administrative
Questions : Ms. Penny Davis
Time
:
Place: 202 Physics Building
Fall 2005
| - September 1, 2005 | Prof. Sean Carroll (University of Chicago) | Host: Armendariz-Picon |
| "Beyond Dark Energy" (abstract) | ||
| - September 8, 2005 | Dr. Lov Grover (Bell Labs, Lucent Technologies) | Host: Balachandran |
| " Quantum Searching - old & new " (abstract) | ||
| - September 15, 2005 | Prof. Stuart Raby (Ohio State University) | Host: Wali |
| "The Puzzle of Charge and Mass" (abstract) | http://www.physics.ohio-state.edu/~raby/ | |
| - September 22, 2005 | Prof. Paul Chaikin (New York University) | Host: Bowick |
| " Jammed Ellipsoids beat Jammed Spheres: Experiments with Colloids and Candies" | ||
| - September 29, 2005 | Profs. Britton Plourde, Jennifer Schwarz, A.P. Balachandran, Eric Schiff, and Sean Xing |
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| "Research Introductions from Physics Faculty" | ||
| - October 6, 2005 | Prof. Andreas Wallraff (Yale) |
Host: Plourde |
| " Quantum Optics and Quantum Computing with Superconducting Circuits " (abstract) | ||
| - October 13, 2005 | Prof. Washington Taylor (MIT) | Host: Trodden |
Yom Kippur |
" What we don't understand about string theory" (abstract) | |
| - October 20, 2005 |
Prof. Thomas Vojta (University of Missouri-Rolla) | Host: Marchetti |
| " Quantum Phase Transitions" (abstract) | ||
| - October 27, 2005 | Dr. B.S. Chandrasekhar | Host: Wali |
| "Low Temperature Physics & Physics 50 Years Ago" (abstract) | ||
| - November 3, 2005 | Prof. Muthukumar Murugappan (U. Mass, Amherst) | Host: Movileanu |
Al Fitr |
" How Polymer Chains Organize into Crystals " (abstract) | |
| - November 10, 2005 | ||
| - November 17, 2005 | Featured speakers include our own Josh Goldberg, David Mermin (Cornell), Alan Lightman (MIT) and our colleagues form LeMoyne David Craig, Enrique Galvez and John Langdon | Beginning 4pm Le Moyne College |
| "Annus Mirabilis: an Einstein Celebration" | ||
| - November 24, 2005 | THANKSGIVING BREAK | |
| - december 1, 2005 | Prof. Simon Catterall (Syracuse University) | |
| " Supersymmetry and Discrete Spacetime: Squaring the Circle ? " | ||
| - December 8, 2005 | Prof. JoAnne Hewett (SLAC, Stanford University) | Host: Trodden |
| "Discovering the Quantum Universe: The Role of Particle Accelerators " (abstract) | ||
| - December 15, 2005 | Prof. Brad Cox (University of Virginia) | Host: Armendariz-Picon |
| Final Exams | " CP Violation and the Neutral K System in the Grand Scheme of Things " (abstract) | |
| Spring 2006 | ||
| - January 19, 2006 | Prof. Emeritus Kameshwar Wali (Syracuse University) " Bose and Einstein; Discovery of Bose-Einstein Statisitics " |
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In June 1924, a relatively unknown Satyendra Nath Bose from Dacca , India , wrote a letter to Einstein beginning with “Respected Sir, I have ventured to send you the accompanying article for your perusal. I am anxious to know what you think of it. You will see that I have ventured to deduce the coefficient 8p? 2 /c 3 in Planck's law independent of the classical electrodynamics, only assuming that the ultimate elementary regions in Phase-space have the content h 3 . I do not know sufficient German to translate the paper. If you think the paper worth publication, I shall be grateful if you arrange for its publication in Zeitschrift für Physik.” Einstein did translate the article himself and got it published. He wrote to Ehrenfest: “The Indian Bose has given a beautiful derivation of Planck's law, including the constant [i.e.8p? 2 /c 3 ].” Einstein extended the ideas of Bose that implied, among other things, a new statistics for the light-quanta to the molecules of an ideal gas and wrote to Ehrenfest, ‘from a certain temperature on, the molecules “condense” without attractive forces, that is, they accumulate at zero velocity. The theory is pretty, but is there also some truth to it?' Abraham Pais has called Bose's paper “the fourth and the last revolutionary papers of the old quantum theory.” My talk will present the works of Bose and Einstein in their historical perspective and the eventual birth of the new quantum Bose-Einstein statistics. |
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| - January 24, 2006 Tuesday - 3:45PM |
Dr. Rana Adhikari (LIGO, California Institute of Tech.) "The Latest Results from LIGO" |
Host: Saulson |
| Gravitational waves, fluctuations in space-time, were predicted by Einstein's theory of General Relativity in 1918. In November of 2005, the Laser Interferometer Gravitational-wave Observatory (LIGO) began a science run with goal of collecting a year's worth of data at an astrophysically interesting sensitivity level. Over the past five years graduate students and scientists have worked to increase the sensitivity by several orders of magnitude. At the start of the latest data run, the two 4 km interferometer's were sensitive to gravitational wave strains of ~10^-21. I will describe how these high-power, 4 km interferometers work, how their sensitivities have been improved to the current state and some of the future upgrades which would increase the event rates by a factor of 1000. | ||
| - January 26, 2006 | Prof. Sean Ling (Brown University) " Nanopore Sequencing of DNA " |
Host: Marchetti |
| In this talk, I'll discuss the latest development in the field of nanopore biophysics, specifically on the problem of DNA sequencing using addressable solid-state nanopores | ||
| - January 31, 2006 Tuesday |
Dr. Nick Darnton (
Rowland Institute at Harvard )
" Polymorphic changes in bacterial flagella" |
Host: Saulson |
| Many bacteria swim by rotating one or more helical flagella. These flagella function as more than simple passive propellers, as they can adopt several helical shapes of varying pitch, radius and handedness in response to changing load conditions. Such polymorphic changes are commonly observed during swimming, when they are induced by torque-changing variations in motor speed; they appear to aid in the reorientation of swimming direction. Measurements on individual, isolated flagellar filaments are revealing the forces required to cause polymorphic transformations. Force-extension measurements in an optical trap show successive, random transformations of sections of the filament superimposed on an elastic stretching curve. Since the filament is a uniform polymer of a single protein whose structure is known, it provides a simple, macroscopically visible model of highly cooperative conformational changes in a biological polymer. | ||
| - February 2, 2006 | Dr. Laura Cadonati (MIT) "LIGO and its Quest for Gravitational Waves" |
Host: Saulson |
The Laser Interferometer Gravitational-wave Observatory (LIGO) has the ambitious goal of performing the first direct detection of gravitational waves. As predicted by General Relativity, gravitational waves are ripples in the fabric of space-time that can be produced by a wide range of sources, both inside and outside our galaxy, such as black hole collisions, supernova explosions, and rotating pulsars. Their detection will provide a fundamental new tool for the understanding of our universe. To achieve this goal, LIGO uses three Michelson laser interferometers, two in Hanford , WA , and one in Livingston , LA. Each interferometer monitors changes in the relative separation of mirrors at the ends of each of two perpendicular arms of km-scale length, in response to the space-time distortions induced by the passage of gravitational waves. The goal for the initial phase of LIGO is to measure differences in length of one part in 10 21 , or 10 -18 m, one thousand times smaller than the nuclear diameter. The detectors have now reached this design sensitivity and the LIGO Scientific Collaboration is actively searching for gravitational wave signatures in the interferometers' data. This talk will present the physics targeted by LIGO, with an overview of possible gravitational wave sources, data analysis methods, current results and the expected reach of the initial and advanced LIGO configuration. |
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| - February 9, 2006 | ||
| - February 16, 2006 | Dr. Xavier Siemens (University of Wisconsin, Milwaukee) " Gravitational waves: A new observational window " |
Host: Saulson |
| In this talk I discuss the basic properties of gravitational waves, argue why we should look for them, and show how we might detect them using laser interferometry. I briefly review the current status of the most sensitive gravitational wave detectors available: The Laser Interferometer Gravitational-wave Observatory (LIGO) instruments. I describe the analysis efforts currently underway, and concentrate on three aspects of the search for gravitational waves. The first is the calibration, which is the procedure used to turn the digital read-out of the interferometers into the gravitational wave strain incident on the interferometer. The second is the search for gravitational waves from rotating neutron stars. Finally, I will discuss the search for gravitational wave bursts from cosmic (super)strings . | ||
| February 21, 2006 Tuesday - 3:45PM |
Dr. Vuk Mandic (California Institute of Technology) " Searching for Stochastic Background of Gravitational Waves with LIGO " |
Host: Saulson |
| Laser Interferometer Gravitational-wave Observatory (LIGO) has built three multi-km interferometers, designed to search for gravitational waves. One of the targets of this search is the stochastic background of gravitational waves, which is expected to exist both due to cosmological and due to astrophysical sources. The search for stochastic background radiation is conducted by examining cross-correlations between different interferometers. I will discuss the current status of the LIGO interferometers and the most recent results of the search for stochastic gravitational-wave background. I will also discuss the implications of these results on theoretical models for stochastic background of gravitational waves. | ||
| - February 23, 2006 | ||
| - March 2, 2006 | Dr. Peter Shawhan (California Institute of Technology) " LIGO Perks Up Its Ears " |
Host: Saulson |
| The Laser Interferometer Gravitational-wave Observatory is the largest component in a worldwide effort to detect gravitational waves reaching the Earth. Potential sources of detectable gravitational waves include binary systems of neutron stars or black holes; core collapse supernovae; cosmic strings; rapidly spinning neutron stars; and a cosmic gravitational wave background. After several years of commissioning, the LIGO detectors have reached their sensitivity goals and are beginning long-term observing. Many searches for gravitational waves have already been carried out using data from a series of short "science runs", and many more searches are underway. | ||
| - March 9, 2006 | ||
| - March 16, 2006 | SPRING BREAK | |
| - March 23, 2006 | Prof. Haiyan Gao (Duke University) A New Search on the Neutron Electric Dipole Moment http://p25ext.lanl.gov/edm/edm.html |
Host: Souder |
| Recently, a new experiment was proposed to search for the neutron Electric Dipole Moment (EDM) with an unprecedented sensitivity. The proposed search will have a two orders of magnitude improvement over the current neutron EDM limit. A search for a non-zero value of the neutron EDM is a direct search of the time reversal symmetry (T) violation. Therefore, it provides a unique insight of CP violation because of CPT invariance. The Standard Model (SM) prediction for the neutron EDM is below the current experimental limit by six orders of magnitude. However, many proposed models of electroweak interaction which are extensions beyond the SM predict much larger values of neutron EDM. The new experiment has the potential to reduce the acceptable range of predictions by two orders of magnitude. Furthermore, if new sources of CP violation are present in nature beyond the Cabibbo, Kobayashi and Maskawa (CKM) mechanism in the Standard Model and are relevant to hadronic systems, the new experiment offers an unique opportunity to search for such new physics. The current understanding of the baryogenesis suggests that additional sources of CP violation might exist in nature beyond the Standard Model and beyond what have been observed so far. To explain the baryon number asymmetry in the universe through the grand unified theory or electroweak baryogenesis, substantial New Physics in the CP violation sector is required. | ||
| - March 30, 2006 | Prof. V.P. Nair (City College of the CUNY) "Helium, QCD, and Feynman's last Problem" |
Host: Joe Schechter |
| In 1954 Feynman applied agruments based on many body wave functions, with spectacular success, to understand superfluid helium. In 1981, he tried to use similar arguments for understanding QCD, the theory of strong nuclear forces. This was the last published work of Feynman in physics. Although he did not succeed, there has been recent progress. I will review his Helium work, his arguments for ACD, and talk about where we stand today. | ||
| - April 6, 2006 | Francis Halzen (University of Wisconsin, Madison ) "High Energy Neutrino Astronomy: towards Kilometer-Scale Neutrino Observatories" |
Host: Wali |
Kilometer-scale neutrino detectors such as IceCube are discovery instruments covering nuclear and particle physics, cosmology and astronomy. Examples of their multidisciplinary missions include the search for the particle nature of dark matter and for additional small dimensions of space. In the end, their conceptual design is very much anchored to the observational fact that Nature produces protons and photons with energies in excess of 10 20 and10 13 electronvolts, respectively. The cosmic ray connection sets the scale of cosmic neutrino fluxes. The problem has been to develop a robust and affordable technology to build the kilometer-scale neutrino detectors required to do the science. The AMANDA telescope using clear deep Antarctic ice as a Cherenkov detector of muons and showers initiated by neutrinos of all 3 flavors, has met this challenge. We review the results obtained with more than 5000 well-reconstructed neutrinos in the 50 GeV~500 TeV energy range collected during its first 4 years of operation. More importantly, we will show that AMANDA represents a proof of concept for the ultimate kilometer-scale neutrino observatory, IceCube, now under construction . |
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| - April 13, 2006 | Prof. Mark Kruse (Duke) Particle Physics at the Energy Frontier |
Host: Blusk |
| Near the end of 2007 the Large Hadron Collider (LHC) at CERN in Geneva, Switzerland, is scheduled to turn on and produce proton-proton collisions at unprecendented energies. The highly anticipated physics that will result is expected to uncover many discoveries and change the way we think about the Universe. I will discuss some important selected physics that the LHC will shed light on, and what our current understanding is from the currently running Tevatron Collider at Fermilab. | ||
| - April 20, 2006 | Prof. David Kaplan (Johns Hopkins University) Scalar Fields and Symmetry Breaking in Particle Physics and Cosmology |
Host: Agashe |
| We have never seen a fundamental particle without spin. However, spinless particles, represented by scalar fields in quantum field theory, appear in nearly every new physics model beyond the current description of particle physics. Moreover, the mass of a generic scalar field is quantum mechanically unstable and may suggest the existence of dramatically new symmetry structures in the laws of physics. In the mean time, theoretical arguments suggest that we are both on the verge of seeing one of these fields (the Higgs) and have already seen indirect evidence for one (the Inflaton). I will describe the physics of these types of particles and discuss the theoretical possibilities of physics beyond the current standard model of particle physics. | ||
| - April 27, 2006 | Prof. Ira Wasserman (Cornell University) " Neutron Star Rotation : Gravitational Radiation, Nonlinear Dynamics, and Superfluidity " |
Host: |
| Neutron stars are as dense as atomic nuclei and as massive as the Sun. They rotate very fast -- in principle up to about 2000 times per second, although the fastest known are only about a third as fast. Gravitational radiation might limit their rotation via a type of negative energy instability, but nonlinear effects truncate its growth at rather small amplitudes. At the other end of the rotational frequency range, a few slower rotating neutron stars -- frequencies of about a few per second -- are believed to wobble with periods of months to years, and many others exhibit timing noise that may also be a consequence of wobbling. This behavior challenges theories of superfluidity and superconductivity of neutron star matter. | ||