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Spring 2007

Schedule Spring 2007

January 30, 2007
3:00 pm (Tuesday)

Dr. Andi Klein
Los Alamos National Lab

Fission Fragment Induced Ejecta from Plutonium

Irradiation of material by particles leads to sputtering or ejecta of the material. This effect is used today in micro machining by employing low energy ion beam and is well described by either the so called binary collision model or molecular dynamics. However, at higher energies, these models break down and the underlying physics is poorly understood. We have designed and built an experiment to measure ejecta from a Plutonium foil irradiated by high energy (~100MeV) heavy ions. I will present the data and discuss the possible implications.

February 9, 2007
3:00 pm (Friday)

Note unusual date

Dr. Chunlei Guo
The Institute of Optics, University of Rochester

From Bright Light Comes Black Metal

Talk will be presented in Kaufman Hall

What exactly would come out if one could gather all the energy flowing on the entire North American power grid and force it running through a tiny fragile fuse? I will try to answer this question by presenting some of our recent work in studying metals using an ultrahigh-brightness femtosecond laser. A highlight of this talk is one of our recent findings in transforming shiny metals totally pitch black.

February 27, 2007
3:00 pm (Tuesday)

Dr. Mark Saffman
The University of Wisconsin-Madison

Towards quantum logic with Rydberg atoms in optical traps

Arrays of neutral atoms in optical traps are being studied as a route towards demonstrating quantum logic operations. I describe recent progress in fast coherent manipulation of ground state and Rydberg atoms as a means of realizing a set of universal quantum gates. Strong interaction of atoms excited to Rydberg levels provides a mechanism for fast two-qubit gates. We discuss the physics of multiatom coupling due to Forster energy hopping, and demonstrate suppression of multiple excitation of Rydberg states in small atom clouds confined to a microscopic optical trap. These results are a significant step towards quantum computing using optically trapped neutral atoms.

March 13, 2007
3:00 pm (Tuesday)

Dr. Dieter Schneider
Lawrence Berkeley National Laboratory

New Physics Research Opportunities

The National Ignition Facility (NIF) at the University of California Lawrence Livermore National Laboratory (LLNL) is a 192-beam, 1.8-MJ, 500 TW, 351nm laser with its construction 90% completed. NIF will provide its MJ of energy in a cubic millimeter volume on a nanosecond time scale for inertial confinement fusion and high energy density research. NIF is being built by the DOE and NNSA to provide an experimental test bed for the U.S. Stockpile Stewart Ship Program. NIF will reserve a certain fraction of its shot capability for pursuing frontier basic science experiments through the outside research community.
A brief description of the NIF laser will be presented together with the planed "National Ignition Campaign (NIC)". Various science agendas for the NIF, utilizing ignition or no-ignition conditions, will be displayed. Some scientific goals and approaches will be discussed. Complementary physics experiments at other high energy density facilities are indicated.

March 20, 2007
3:00 pm (Tuesday)

Dr. David Weitz
Harvard University

New Insights into Hard Problems with Soft Materials

This talk will present results of studies of both crystallization and the glass transition performed by real-space imaging of individual particles in colloidal suspensions, providing rich new insight into the behavior of these most fundamental phase transitions.

April 3, 2007
3:00 pm (Tuesday)

Dr. Subir Sachdev
Harvard University

Quantum Phase Transitions

In the familiar "classical" phase transitions, such as the boiling of water into steam, there is a qualitative change in the nature of thermal motion of water molecules. In a "quantum" phase transition, there is a qualitative change in the nature of the quantum entanglement in the ground state of a large number of particles. I will describe some illustrative examples in the cuprate superconductors and other transition metal compounds and in trapped ultracold atoms. Right at the transition point, we obtain a novel "quantum critical" state of matter. Its description has intriguing connections to the quantum theory of black holes and the quark-gluon plasma.

April 10, 2007
3:00 pm (Tuesday)

Dr. Tony Thomas
Jefferson Lab

Quark Level Description of Nuclei and Nuclear Matter - Hadrons to Neutron Stars

There is a measure of debate within the nuclear community concerning the relevance of quark degrees of freedom in understanding nuclear structure. We briefly outline some of the key issues and review the impressive progress made recently within the framework of the quark-meson coupling model. In particular, we explain in quite general terms how the modification of the internal structure of hadrons in-medium leads naturally to three- and four-body forces, or equivalently to density dependent effective interactions. The consequences of these insights for experiments that can be performed at Jefferson Lab will be briefly described, as will some of the implications for the structure and properties of neutron stars.

April 17, 2007

Dr. Marcia Bartusiak

Einstein's Unfinished Symphony

New observatories are beginning operation worldwide that will provide a whole new sense with which to explore the heavens. Instead of collecting light waves, these novel instruments are allowing astronomers to place their hands upon the fabric of space-time and feel the very rhythms of the universe. These vibrations in space-time-gravity waves-are the last prediction of Einstein's general theory of relativity yet to be observed directly. They are his unfinished symphony. Gravity waves will provide the first direct evidence of black holes and allow us to eavesdrop on the remnant echo of the Big Bang itself. Bartusiak will tell the story of the 45-year-long quest to capture these waves, introducing us to the people, the technology, and the science of this enterprise from a science writer's perspective.

April 24, 2007
3:00 pm (Tuesday)

Old Dominion University

Senior Thesis Presentations

Polarization and Attenuation of Terahertz Radiation
Mr. Wade Brock

Influence of Chlorides on Atmospheric Corrosion of Structural Steel
Mr. Chris Overall

Light-induced Trap Loss in a Magneto-optical Trap
Mr. David Royfe

The Commissioning of the Field Emission Viewer
Ms. Rachel Sparks