Events at Physics |
Events During the Week of March 8th through March 15th, 2009
Monday, March 9th, 2009
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Helical States and Feedback Control in RFX: Building the RFP Future in the ITER ERA
- Time: 12:05 pm
- Place: 3345 Engineering Hall
- Speaker: Piero Martin, Consorzio RFX, Physics Dept., University of Padova, ITALY
- Plasma Theory Seminar
- RF Stabilization Mechanisms for Resistive Tearing Modes
- Time: 4:00 pm
- Place: 514 ERB
- Speaker: Tom Jenkins, UW-Madison, Dept of Physics/Plasma
Tuesday, March 10th, 2009
- R. G. Herb Condensed Matter Seminar
- Single-Particle Properties of Graphene: Magnetotransport and Superlattice-Controlled Band Gap
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Rakesh Tiwari, Ohio State University
- Abstract: Graphene, a two-dimensional form of carbon, is poised to play an important role in future electronic devices. In this talk I will discuss two properties of graphene which may be very useful for next-generation devices: large magnetoresistance and the controllable band gap at the Dirac point. I will show that the experimentally observed large magnetoresistance can be explained using a picture of graphene as a mixture of n and p type puddles. Even if we assume a field independent resistivity for the individual puddles (free electron or hole picture), an effective medium approximation predicts a large magnetoresistance for the composite, in agreement with experiment. In the second part of the talk, I will describe an efficient way of controlling the electronic band gap at the Dirac point in graphene using a non-centrosymmetric superlattice potential. I will confirm this method by calculating the superlattice band structure using an expansion of the wave functions in plane waves.
- Host: Robert Joynt
- Chaos & Complex Systems Seminar
- Engaging the flow: a creative dialogue revisited
- Time: 12:05 pm
- Place: 4274 Chamberlin
- Speaker: Harry Webne-Behrman, UW Office of Human Resource Development
- Abstract: Creative conversations don't mechanically follow 'outline form,' they emerge from the synergies and interactions of participants in hard-to-predict ways. Is there a way to facilitate such dialogues, rather than direct them, so 1 + 1 >2? Is there a way to capture the creative ideas that emerge? Last Fall, the Chaos & Complexity Seminar engaged in a creative dialogue around a broad question with some productive ideas. On this occasion, the group is asked to focus more deeply on one of the issues that emerged from the previous dialogue: "How might UW-Madison best engage its resources to meet the challenge of assuring the "Wisconsin Experience" for its students?" The Wisconsin Experience is intended to result in graduates who have the capacity and commitment to make the world a better place. It is intended to build upon the unique strengths of the UW-Madison community to foster such ideals that have resulted in extraordinary citizens, global activists and volunteers, corporate leaders and others with a special sense of social responsibility and an activated, current sense of the Wisconsin Idea. My intention in this dialogue is to gain participant reflections on this initiative in its pedagogical, research, service, and cultural dimensions. What aspects of this Experience are worth pursuing? Where should resources be emphasized and how might they best be organized to do so? For additional information about this important initiative from Aaron Brower (Vice-Provost for Teaching and Learning) and Lori Berquam (Dean of Students), please visit: http://www.learning.wisc.edu -- a summary of the objectives of the Wisconsin Experience is attached, as well. Join us for fascinating conversation and see what happens!
- Astronomy Colloquium
- The Local Group Manifesto
- Time: 3:30 pm
- Place: 6515 Sterling Hall
- Speaker: Kathryn Johnston, Columbia University
- Abstract: In the context of Lambda CDM, while larger structures in the Universe are thought to form hierarchically from the mergers of many smaller structures, the histories of individual galaxies are expected to vary widely. This raises the question of what we can learn about galaxies in general from studying just a few galaxies in great detail (i.e. the Milky Way and its nearest neighbors). In particular, in this talk I will outline what current and future studies of the phase- and abundance-space distributions of stars in the Local Group might tell us about how galaxies form and evolve throughout the Universe.<br>
Wednesday, March 11th, 2009
- No events scheduled
Thursday, March 12th, 2009
- R. G. Herb Condensed Matter Seminar
- Coulomb Correlations and the Wigner-Mott Scenario for the 2D-MIT
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Vladimir Dobrosavljevic, Florida State University
- Abstract: Significant experimental advances over the past ten years have provided beautiful and convincing evidence for the existence of a sharp metal-insulator transition (MIT) in the two-dimensional 2D electron gases (2DEG). The best evidence for a sharp MIT is found in the cleanest samples, suggesting that key experimental features can all be understood by deliberately disregarding disorder, and focusing on interaction effects alone: viewing the quantum melting of a Wigner crystal as the fundamental mechanism for the MIT in a sufficiently clean 2DEG. A theory describing this phenomenon will be presented, which provides a natural explanation of several puzzling experimental features, including the large effective mass enhancement, the large resistivity drop on the metallic side, and the giant magneto-resistance in presence of a parallel magnetic field.
- Host: Robert Joynt
- Whitford Lecture
- A brief History of Cosmic Expansion and Acceleration
- Time: 3:30 pm
- Place: 2103 Chamberlin Hall
- Speaker: Adam Riess, JHU and STSci
- Abstract: <br>
The expansion rate and its evolution must be empirically determined for our Universe to reveal its composition, scale, age, and fate. In 1998, high-redshift SNe Ia provided the first and only direct evidence for an accelerating Universe and the existence of dark energy. To identify the nature of dark energy we seek to improve on past and present measurements of the recent history of cosmic expansion. Today's keystones of expansion are distant type Ia supernovae and Cepheid variables in their hosts. I will report on new calibrations of the Hubble diagram of SNe Ia with new SN Ia and Cepheid data and an extension of its reach to <br>
z > 1 when cosmic expansion was still decelerating. These measurements are providing new clues about the nature of the mysterious dark energy.<br>
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- Host: Professor Richard Townsend
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- New Results from the Pierre Auger Observatory
- Time: 4:00 pm
- Place: 4274 Chamberlin
- Speaker: Segev BenZvi, University of Wisconsin - Madison
- Host: Stefan Westerhoff
Friday, March 13th, 2009
- No events scheduled