Events at Physics |
Events During the Week of January 24th through January 31st, 2010
Monday, January 25th, 2010
- Plasma Theory Seminar
- Nimrod Simulations of Dynamo in Cylindrical and Spherical Geometries
- Time: 4:00 pm
- Place: 514 ERB
- Speaker: Ivan Khalzov, University of Wisconsin, Dept. of Physics/Plasma
Tuesday, January 26th, 2010
- Chaos & Complex Systems Seminar
- Auditory Activation with Electric Hearing: Studies on Auditory Plasticity in Deaf Humans
- Time: 12:05 pm
- Place: 4274 Chamberlin Hall
- Speaker: Ruth Litovsky, UW-Madison Department of Communicative Disorders
- Abstract: It is not uncommon for individuals who are deaf to undergo surgical treatment whereby they are fitted with cochlear implants (CIs). These devices send electrical stimulation to the auditory nerve in such a way that the brain can learn to interpret the stimulation, and CI users can effectively understand speech and enjoy the auditory world. Until recently, the standard of care had been to implant candidate patients with a single device in one ear. More recently, this standard has shifted such that two devices, bilateral CIs, are being provided to growing number of patients. Being able to hear with two ears affords humans functional abilities such as localization of sounds and segregation of sources from background noise. These abilities depend on binaural brain function, that is, on neural circuits that integrate inputs from the two ears with great precision. Our lab studies the emergence of binaural hearing abilities in children and adults who had experienced various periods of auditory deprivation prior to being activated with electric hearing. Our studies address questions regarding the ability of the auditory system to retain sensitivity to binaural hearing after deprivation. In addition, in children who have never heard with acoustic hearing, but whose brains are wired for acoustics, we study the ability of the brain to respond to electric stimulation such that the children attain age-appropriate abilities in domains of language, speech and hearing.<br>
<br> - Astronomy Colloquium
- Star Formation and Gas in Nearby Galaxies
- Time: 3:30 pm - 5:00 pm
- Place: 3425 Sterling Hall
- Speaker: Adam Leroy, NRAO
- Abstract: I will discuss what recent multiwavelength surveys tell us about why stars form where they do in galaxies and what makes the ISM good at forming stars. The question is an open one, with results in the last few years variously identifying gravitational stability, metallicity, pressure, opacity, and collisions in the ISM as the regulating quantity. From large programs with the IRAM 30m ("HERACLES") and the VLA ("THINGS") we know the distribution of atomic and molecular gas in several dozen galaxies that have also been observed by Spitzer and GALEX (and are now being mapped by Herschel). These data allow us to estimate a range of physical conditions over kiloparsec-sized resolution elements across each galaxy (e.g., the star formation rate, HI mass, H2 mass, stellar mass, kinematics, dust-to-gas ratio). We are using these estimates to push beyond galaxy-averaged scaling relations, testing proposed local drivers for the formation of molecular clouds and stars from diffuse neutral gas. I will summarize these tests and give our current best answers to the basic question: "where is the interstellar medium good at forming stars?"
- Host: Prof Snezana Stanirmirovic
- String Theory Seminar
- Toric Lego: A Modular Approach to Model Building in String Theory
- Time: 4:00 pm
- Place: 5280 Chamberlin Hall
- Speaker: Inaki Garcia-Etxebarria, UPenn
- Host: Shiu
Wednesday, January 27th, 2010
- R. G. Herb Condensed Matter Seminar
- Title to be announced
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Alexander Abanov, Stony Brook University
- Host: Andrey Chubukov
Thursday, January 28th, 2010
- R. G. Herb Condensed Matter Seminar
- Competition between superconductivity and magnetism in the iron arsenides
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Rafael Fernandes, Ames National Laboratory
- Abstract: The new iron arsenide superconductors present a very rich phase diagram, displaying superconducting, antiferromagnetic and structural order. In this seminar, I present a microscopic theory to study the interplay between electronic and magnetic degrees of freedom. In this model, electrons sharing the same bands are responsible for both superconductivity and itinerant magnetism, causing these two states to compete. Then, two distinct outcomes are possible: either these two states are mutually exclusive and phase separate or they can coexist microscopically. Using a mean-field approach, I analyze the relationship between these two scenarios and the symmetry of the Cooper-pair wave function. In particular, I show that while the so-called s++ state is generally incompatible to the antiferromagnetic phase, the unconventional s+- state is able to coexist with magnetism. Thus, valuable information about the nature of the superconducting phase can be extracted directly from the phase diagrams of the iron arsenides.
- Host: Maxim Vavilov
Friday, January 29th, 2010
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Violating Rotational or Translational Invariance During Inflation (Joint with Phenomenology)
- Time: 2:30 pm
- Place: 5280 Chamberlin
- Speaker: Mark B. Wise, Caltech
- Abstract: I explore the possibility that rotational or translational invariance is violated during the inflationary era but restored at the end of the inflationary era. This possibility is constrained by data on the microwave background anisotropy. Some particular inflationary models are discussed.
- Host: Pavel Fileviez Perez
- Special Cryogenic Dark Matter Search Seminar
- Results from the Cryogenic Dark Matter Search experiment
- Time: 4:00 pm
- Place: 4274 Chamberlin Hall (coffee at 3:30 pm)
- Speaker: Oleg Kamaev, University of Minnesota
- Abstract: The Cryogenic Dark Matter Search (CDMS) experiment uses solid-state detectors operated near 40 mK to search for Weakly Interacting Massive Particles (WIMPs). The experiment measures the ionization and athermal phonons from particle interactions to discriminate candidate (nuclear recoil) from background (electron recoil) events with a rejection factor of better than 10^6. I will present results from the recent blind analysis of data from 612 kg-days of raw exposure using the Ge detectors operated in the Soudan Underground Laboratory. I will also report on the operation of a recently installed tower of larger Ge detectors with improved phonon readout and discuss R&D work for the next generation of CDMS detectors.
- Host: Karsten Heeger