Events at Physics |
Events During the Week of March 27th through April 3rd, 2011
Monday, March 28th, 2011
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Inertial Fusion Energy Prospects - The LIFE Reactor Concept
- Time: 12:05 pm
- Place: 2241 Chamberlin Hall
- Speaker: Greg Moses, UW-Madison Dept of Engineering Physics
- Abstract: The basics of economical inertial fusion energy and ICF high gain target performance will be reviewed. The Lawrence Livermore National Laboratory LIFE reactor concept will be described. Recent experiences and insights while on sabbatical at LLNL (Jan-May 2010) will be revealed.
Tuesday, March 29th, 2011
- No events scheduled
Wednesday, March 30th, 2011
- Department Meeting
- Time: 12:15 pm
- Place: 5310 Chamberlin Hall
- Special Plasma Seminar
- Geomagnetic Secular Variation as a Window on the Dynamics of Earth's Core
- Time: 2:15 pm
- Place: 2241 Chamberlin Hall
- Speaker: Andrew Jackson, ETH Zurich
- Abstract: One of the forefront questions of planetary geophysics is to understand how magnetic fields can be spontaneously created by so-called dynamo action. Giant strides have been taken in recent years in understanding the theory of convectively driven dynamos; yet equally important is the marriage between theory and observation. I will argue that we are on the cusp of a new level of understanding
brought about by new methods for incorporating observations and theory, akin to those used in meteorology and oceanography. In 1950 Sir Edward Bullard wrote an influential paper entitled "The westward drift of the Earth's magnetic field", with coauthors C Freedman, H Gellman and J Nixon. A comprehensive study of observations was tied together with the then nascent dynamo theory to infer properties
of the dynamics of the core. Sixty years on, we have a much enriched understanding of the theory of convectively driven dynamos, and an even more comprehensive database of observations stretching back several centuries. Equally important are the new satellite observations that provide global coverage with unprecedented accuracy over the last decade. In this talk I will try to show how the interplay between theory and observation can lead to beter understanding of the dynamical regime in the core. Thursday, March 31st, 2011
- R. G. Herb Condensed Matter Seminar
- Quantum Phases of the Cairo Pentagonal Lattice
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Ioannis Rousochatzakis, Max-Planck Insitute for the Physics of Complex Systems, Dresden
- Abstract: We present an analytical and numerical study of the spin S=1/2 antiferromagnetic Heisenberg model on the Cairo pentagonal lattice. This is the dual of the Shastry-Sutherland lattice and has been discussed as a possible new candidate for having a spin liquid ground state [1]. More recently a S=5/2 version of this model has been realized in the Bi2Fe4O9 system [2]. Here we use a model with two different types of exchange couplings and investigate the nature of the ground state as a function of their ratio. This strategy allows us to understand the nature of a number of phases and derive effective models for their description with and without a magnetic field. Of particular interest is a surprising interplay between a collinear and a four-sublattice orthogonal phase due to an underlying order-by-disorder mechanism. Furthermore we address the issue of possible nonmagnetic ground states such as singlet and spin nematic phases.
References:
[1] K. S. Raman, R. Moessner, and S. L. Sondhi, PRB 72, 064413 (2005)
[2] E. Ressouche, V. Simonet, B. Canals, M. Gospodinov, and V. Skumryev, PRL 103, 267204 (2009) - Host: Natalia Perkins
- Astronomy Colloquium
- The HERMES project - reconstructing the ancient Galaxy
- Time: 3:30 pm - 5:00 pm
- Place: 4421 Sterling Hall
- Speaker: Joss Bland-Hawthorn, Federation Fellow, University of Sydney
- Abstract: The first building blocks of our Galaxy were likely to have been laid down in the first 300 million years after the Big Bang. The first stars that came into being in those early structures have long since disappeared but they may have left behind unique chemical signatures in today's stellar populations. Over the next 13 billion years, the Galaxy grew through a series of mergers and acquisitions into the corporate giant that surrounds us today - 100 billion stars and counting. This was undoubtedly a very complex process that we are far from understanding even with the most sophisticated computer simulations. All stars show evidence of chemical signatures that say something about their past. In this talk, I will describe the basic motivation of the HERMES survey which will attempt to reconstruct the early Galaxy history through the technique of chemical tagging. The HERMES instrument is a major new $10M facility at the AAT that will see first light in 2013.
- Host: Professor Snezana Stanimirovic
Friday, April 1st, 2011
- Phenomenology Seminar
- Dark Matter at LEP and the Tevatron
- Time: 2:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Patrick Fox, Fermilab
- Host: Neil Christensen
- Physics Department Colloquium
- How the Hippies Saved Physics
- Time: 4:00 pm
- Place: 2241 Chamberlin Hall (coffee at 3:30 pm)
- Speaker: David Kaiser, MIT
- Abstract: In recent years, the field of quantum information science has catapulted to the cutting edge of physics, sporting a multi-billion-dollar research program, tens of thousands of published research articles, and a variety of device prototypes. This tremendous excitement marks the tail end of a long-simmering Cinderella story. Long before the big budgets and dedicated teams, the field moldered on the scientific sidelines. In fact, the field's recent breakthroughs derive, in part, from the hazy, bong-filled excesses of the 1970s New Age movement. Many of the ideas that now occupy the core of quantum information science once found their own amid an anything-goes counterculture frenzy, a mishmash of spoon-bending psychics, Eastern mysticism, LSD trips, and CIA spooks chasing mind-reading dreams. For the better part of two decades, the concepts that would, in time, blossom into developments like quantum encryption were bandied about in late-night bull sessions and hawked by proponents of a burgeoning self-help movement -- more snake oil than stock option. This talk describes the field's bumpy transition from New Age to cutting edge.
- Host: Huber