Department of Physics

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Colloquia & Seminars, Spring 2007

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Latest results from MiniBooNE

Speaker: Prof. Eric Hawker
Date: Wednesday, May 2, 2007
Time: 4 p.m.
Room: 205 Currens Hall

Abstract
The interesting quantum effect called neutrino oscillations requires that all three known types of neutrino have mass. Several experiments have shown that neutrino oscillations do occur in nature, including the LSND experiment, which presented evidence of oscillations occurring at a much higher Dm2 than other experiments have measured. The MiniBooNE collaboration recently announced its first results, showing an absence of a signal that would have confirmed the LSND result. This talk will review the physics of neutrino oscillations, and briefly cover the results of other oscillation experiments, before focusing on the MiniBooNE experiment, analysis, and result.

About the speaker:
Dr. Eric Hawker is an Assistant Professor in the Department of Physics at Western Illinois University.

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Color Glass Condensate and Glasma

Speaker: Dr. Larry McLerran
Date: Friday, April 13, 2007
Time: 4 p.m.
Room: 205 Currens Hall

Abstract
At the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, collisions of nuclei produce matter at ultra-high energy density. The Color Glass Condensate and the Glasma are two forms of matter produced in such interactions. Such matter is associated with very strong coherent color electric and magnetic fields composed of the gluons of Quantum Chromodynamics, the theory of strong interactions. The properties of these fields may resolve the long standing problem of the high energy limit of strong interactions.

About the speaker:
Dr. Larry McLerran is a distinguished scientist and a theory group leader at the RIKEN BNL Research Center. Dr. McLerran is a Fellow of the American Physical Society and a Foreign Member of the Finnish Academy of Arts and Sciences.

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Seminar: Theoretical Aspects of Color Glass Condensate and Glasma

Speaker: Dr. Larry McLerran
Date: Thursday, April 12, 2007
Time: 2 p.m.
Room: 205 Currens Hall

Abstract
I discuss some possible new forms of matter which are important for high energy processes in QCD. Both these forms of matter have very high density coherent gluon fields. From elementary arguments, I show the space-time structure of the transverse fields associated with the Color Glass Condensate. These fields change their form almost instantaneously in a collisions, into the longitudinal fields of the Glasma. The Glasma fields have a large topological charge density, but zero net topoligical charge. On a time scale of order the inverse saturation momentum, the Glasma fields are unstable with respect to forming rapidity dependent fluctuations. These may induce rapid thermalization and net topological charge in hadronic collisions. Finally, I explore the possibility that at distance scales much less than the inverse saturation momentum in the Color Glass Condensate, there are hot spots of saturated matter. I argue that the distribution of such spots may be described by Liouville theory, which is a theory of 2-dimensional quantum gravity.

About the speaker:
Dr. Larry McLerran is a distinguished scientist and a theory group leader at the RIKEN BNL Research Center. Dr. McLerran is a Fellow of the American Physical Society and a Foreign Member of the Finnish Academy of Arts and Sciences.

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Supernovae and Neutron Stars: Probing the Physics of the Extreme with High-Energy Missions

Speaker: Prof. Samar Safi-Harb
Date: Friday, February 16, 2007
Time: 4 p.m.
Room: 205 Currens Hall

Abstract
Supernova explosions are among the most energetic events in the Universe. The study of their remnants, particularly at high-energies, provides crucial information on the poorly known ages, distances, progenitor stars, dynamics of the supernovae that created them; and sheds light on the nature of the collapsed cores and the way they interact with their surroundings.

Our understanding of core-collapse supernovae and their byproducts has been, in the 20th century, shaped by the study of the Crab nebula and its powering engine: a ~1000-year old, fast spinning, compact star having a surface dipole magnetic field of the order of 1012 Gauss, and powering a synchrotron nebula visible throughout the electromagnetic spectrum.

However, 21st century X-ray observations have dramatically changed our view of the aftermath of a supernova explosion by revealing a zoo of neutron stars and nebulae with properties unlike the Crab. I will review the past and on-going observations dedicated to the study of neutron stars and associated supernova remnants. I will then highlight the emerging zoo with emphasis on magnetars, a growing class of neutron stars believed to be the strongest magnets in the Universe.

About the speaker:
Dr. Samar Safi-Harb is an Associate Professor at the Department of Physics and Astronomy of the University of Manitoba, Winnipeg, Manitoba, Canada

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Frequency comb and its applications

Speaker: Dr. Zehuang Lu
Date: Wednesday, February 14, 2007
Time: 12 p.m.
Room: 205 Currens Hall

Abstract
The invention of frequency comb has revolutionized the field of precision laser spectroscopy. In this talk I will give a detailed explanation of how frequency comb works. There are many applications of frequency comb. I will give two examples in the talk. One is the precision laser spectroscopy of single indium ion with frequency comb, and the experimental uncertainty is observed to be 10-13, limited by reference Cs atomic clock. Another example is the precision measurement of the refractive index of air with frequency comb, where we reach an uncertainty of 10-9, the best in the world so far. Possible future research directions with frequency comb will be mentioned.

About the speaker:
Dr. Zehuang Lu is a postdoctoral scientist at The Max Planck Research Group "Optics, Information and Photonics" at the University Erlangen Nuremberg

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Super-Resolution: Quantum Tricks to Beat the Diffraction Limit

Speaker:Dr. Kishore T. Kapale
Date: Tuesday, February 6, 2007
Time: 4 p.m.
Room: 205 Currens Hall

Abstract:
Rayleigh diffraction limit for resolution is not fundamental as it hinges on the use of a particular optical setup. Several classical optical techniques, such as monitoring the evanescent fields, allow resolution beyond the diffraction limit, however, only by a small factor. Recently several quantum tricks have emerged to obtain resolution much beyond the diffraction limit. On one hand, use of spatially dependent light-matter interaction allows extreme subwavelength resolution in determining position of an atom. On the other hand, use of special entangled photon states imparts pre-chosen subwavelength resolution in the interferometric measurements and lithography. Both these areas of frontier super-resolution research will be introduced. In this context, a natural question arises: Is there an ultimate limit to resolution? This question will be addressed with an eye on the limitations of these super-resolution proposals.

 

About the speaker:
Dr. Kishore T. Kapale is a postdoc at Jet Propulsion Laboratory, California Institute of Technology

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Quantum Computing and Quantum Memory in Rare Earth Doped Solids

Speaker:Dr. Mingzhen Tian
Date: Monday, January 29, 2007
Time: 4 p.m.
Room: 205 Currens Hall

Abstract:
In the past decade, quantum information has been one of the most active areas in science and technology. Quantum computing holds the unprecedented computational power for exact simulation of physical processes in quantum systems and efficient solution of some computational hard problems, such as larger number factorization. Quantum memory is an important element in realization of quantum cryptography over long distant. Physical implementation of quantum computing and quantum memory has been the main focus in developing practical quantum information technology. Rare earth ions doped in solids is one of the promising candidates for building quantum computing hardware and quantum memory. The basic ideas of rare-earth based approach and recent results from experiments and simulations will be discussed at the colloquium.

About the speaker:
Dr. Tian is a research assistant professor at Physics Department of Montana State University.

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Rotational alignment revivals in asymmetric top molecules

Speaker:Dr. Edward L. Hamilton
Date: Tuesday, January 23, 2007
Time: 4 p.m.
Room: 205 Currens Hall

Abstract:
Under excitation by a short, strong-field laser pulse, molecules with a polarization anisotropy undergo dynamical alignment that leads to a transient revival signature at later times. I discus the extension of this theory to alignment of an asymmetric top in three dimensions, and present calculations that address the viability of proposed alignment strategies for laboratory application.

About the speaker:
Dr. Edward L. Hamilton is a postdoc at the Center for Nanofabrication and Molecular Self-Assembly, Department of Chemistry, Northwestern University, Evanston, IL 60208