Events at Physics |
Events on Thursday, February 14th, 2008
- R. G. Herb Condensed Matter Seminar
- Electronic transport in inhomogeneous quantum wires
- Time: 10:00 am
- Place: 5310 Chamberlin Hall
- Speaker: Jerome Rech, Argonne National Laboratory
- Abstract: Perhaps more importantly than the observation of characteristic signatures of one-dimensional physics, the reports of anomalies in the transport properties of quantum wires focused a lot of attention on these systems. From the theoretical point of view, these results initiated various attempts to study the effects of electron-electron interactions on the transport properties of one-dimensional conductors. In this talk, I will explain how non-uniform interactions along the wire may lead to substantial contributions to the transport properties. I will show that these inhomogeneities of the system lead to a finite resistivity associated with electron-electron scattering processes which weakly violate the momentum conservation. Using an alternative approach compatible with the bosonization formalism, I will compare these results to previous works relying on an extension of the Tomonaga-Luttinger model to inhomogeneous systems.
- Host: Chubukov
- Astronomy Colloquium
- Stellar Archaeology: Galaxy Evolution from the Ground Up
- Time: 3:45 pm
- Place: 6515 Sterling Hall (coffee at 3:30 pm in 6521 Sterling)
- Speaker: Jason Harris University of AZ - Steward Observatory
- Abstract: Two of the greatest triumphs of late twentieth-century astrophysics were the understanding of large-scale structure formation (through hierarchical collapse in a universe dominated by cold dark matter), and an exquisite, quantitative understanding of stellar evolution. Usually regarded as completely separate fields, they are nevertheless connected by the physics which govern star formation in galaxies. If CDM simulations are to reproduce the galaxy populations as we observe them in the universe, then we will need to develop a robust, quantitative theory of the physical processes which govern star formation on galactic scales. Likewise, while we now have a comprehensive understanding of the evolution of stellar populations, our ideas are much less detailed when it comes to protostellar populations, the agents that trigger star formation, and the feedback processes that may sustain or quench it. I will present some of my ongoing work in stellar archaeology that is addressing the need for a quantitative star formation theory, through detailed explorations of the stellar and protostellar populations in nearby galaxies.
- Physics Department Colloquium
- How Does A Thing Like That Work?
- Time: 4:00 pm
- Place: 2241 Chamberlin Hall (coffee at 3:30 pm)
- Speaker: David Willey, University of Pittsburgh at Johnstown
- Abstract: 'HDATLTW', is an entertaining, interactive physics demonstration lecture consisting of the more visual and dramatic demonstrations from an introductory physics course. The show usually lasts close to microcentury and about 25 demonstrations are performed. It is fast paced and is meant to promote interest in science and further discussion, with only a simple explanation of the physics involved being given as each demonstration is presented.
- Host: Sprott