Events at Physics |
Events During the Week of February 6th through February 13th, 2011
Monday, February 7th, 2011
- Plasma Physics (Physics/ECE/NE 922) Seminar
- MHD Simulations of Magnetic Reconnection with Application to Solar Flares and Magnetospheric Substorms
- Time: 12:05 pm
- Place: 2241 Chamberlin Hall
- Speaker: Joachim Birn, Los Alamos National Laboratory
- Department Meeting
- Time: 12:15 pm
- Place: 5310 Chamberlin Hall
- Condensed Matter Theory Group Seminar
- Weyl Problem and the Casimir Effect in Spherical Shell Geometry
- Time: 4:30 pm
- Place: 5310 Chamberlin
- Speaker: Hussain Zaidi, University of Virginia
- Abstract: We compute the generic mode sum that quantifies the effect of the change of spectrum of a harmonic field when a spherical shell is inserted into the vacuum. This encompasses a variety of problems including the Weyl spectral problem and the Casimir effect of quantum electrodynamics. The connection between the Weyl problem and the Casimir energy allows us to resolve a long-standing controversy regarding the question of universality of the Casimir self-energy. Specifically we demonstrate that in the case of a scalar field obeying Dirichlet boundary conditions on the shell surface the Casimir self-energy is cutoff-dependent, while in the case of a conductive shell the Casimir self-energy is universal.
- Host: Maxim Vavilov
Tuesday, February 8th, 2011
- Chaos & Complex Systems Seminar
- How Video Games Model Agency in Complex Systems
- Time: 12:00 pm
- Place: 4274 Chamberlin Hall
- Speaker: Rich Halverson, UW School of Education
- Abstract: Simulations have become standard tools for research in dynamic, complex systems. Yet simulations often struggle to model how individuals make choices in such systems, often by substituting estimated probability models for direct observation of actor interaction. Contemporary immersive video games provide models for how researchers can study how actual actors interact with complex systems. In today's discussion, I will review several research approaches to understand the cognitive and socio-cultural aspects of player-videogame engagement, and discuss how the development of the next generation of video-games can outline a new form of observational research on complex system interaction.
Wednesday, February 9th, 2011
- Department Meeting
- Time: 12:15 pm
- Place: 5310 Chamberlin Hall
Thursday, February 10th, 2011
- R. G. Herb Condensed Matter Seminar
- Electrical and Optical Characterization of Molecular Nanojunctions
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Dan Ward, Rice University
- Abstract: Electrical conduction at the single molecule scale has been studied extensively with molecular nanojunctions. However, our understanding is hindered by a lack of methods for simultaneous local imaging or spectroscopy to determine the conformation and local environment of the molecule of interest. Plasmon based surface-enhanced spectroscopies are one method of probing the conformation and environment of a molecule. Using a combination of simultaneous electrical and optical measurements we have successfully demonstrated that nanojunctions are excellent surface-enhanced Raman spectroscopy substrates that can have single molecule sensitivity. In this talk I will discuss two recent experimental results, including an investigation into optically driven currents in bare nanojunctions. The resulting photocurrent is due to rectification of the enhanced optical electric field in the nanogap. From low frequency electrical measurements we are able to infer the magnitude of the enhanced electric field, with inferred enhancements exceeding 1000. I will also discuss electrical and optical heating in molecular nanojunctions. Our measurements show that molecular vibrations and conduction electrons in nanojunctions, under electrical bias or laser illumination, can be driven from equilibrium to effective temperatures exceeding 600 K. We observe that individual vibrations are not in thermal equilibrium with one another, the conduction electrons, or the substrate.
- Host: Mark Eriksson
Friday, February 11th, 2011
- Theory/Phenomenology Seminar
- Top Quark Polarization Measurement in Dilepton Channel and New Physics Search
- Time: 2:30 pm - 3:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Qing-Hong Cao, Argonne National Laboratory and University of Chicago
- Host: Maike Trenkel
- Physics Department Colloquium
- Strings and the Real World
- Time: 4:00 pm
- Place: 2241 Chamberlin Hall (coffee at 3:30 pm)
- Speaker: Gordy Kane, University of Michigan
- Abstract: In this talk I'll describe how string theory is exciting because it can address most or all of the questions we hope to understand about the quarks and leptons that make up our world, the forces that form our world, cosmology, CP violation, and more. I'll explain why string theory is testable in basically the same ways as the rest of physics, and why much of what is written about that is misleading. String theory is already or soon being tested in several ways, including dark matter, LHC physics, neutrino physics, cosmological history, and more, from work in the increasingly active subfield "string phenomenology".
- Host: Ramsey-Musolf
Saturday, February 12th, 2011
- Wonders of Physics
- Annual show
- Time: 1:00 pm
- Place: 2103 Chamberlin
- Speaker: Clint Sprott
- Wonders of Physics
- Annual show
- Time: 4:00 pm
- Place: 2103 Chamberlin
- Speaker: Clint Sprott
- Wonders of Physics
- Annual show
- Time: 7:00 pm
- Place: 2103 Chamberlin
- Speaker: Clint Sprott
Sunday, February 13th, 2011
- Wonders of Physics
- Annual show
- Time: 1:00 pm
- Place: 2103 Chamberlin
- Speaker: Clint Sprott
- Wonders of Physics
- Annual show
- Time: 4:00 pm
- Place: 2103 Chamberlin
- Speaker: Clint Sprott