Events at Physics
Events During the Week of October 21st through October 28th, 2012
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Local and global plasma response and plasma-facing component performance of the liquid lithium divertor in NSTX
- Time: 12:00 pm
- Place: 1310 Sterling Hall
- Speaker: Michael Jaworski, Princeton Plasma Physics Laboratory
- Special Lunch Astronomy Talk
- Cores, anisotrophy and (complex) rotation: the (Classical) dwarf Spheroidals
- Time: 12:00 pm
- Place: 4421 Sterling Hall
- Speaker: Nicola Amorisco, University of Copenhagen
The presence of multiple stellar populations in dwarf Spheroidals has proved to be the key to advancing our understanding of their dynamical state, dark matter content, and evolutionary history. Chemo-dynamical methods use both metallicity and kinematical information from discrete spectroscopic samples to identify and disentangle any distinct sub-populations. These are then fed to dynamical analyses, which greatly benefit from the independent constraints enforced by different sub-populations. I'll review some recent results on the subject and report on the evidence for a large dark matter core in both the Sculptor and Fornax dwarf Spheroidals, on an attempt to characterize directly the orbital structure of these systems, and on the detection of a complex chemo-rotational pattern in the Fornax dwarf.
- Host: Prof Elena D'onghia
- Chaos & Complex Systems Seminar
- Adaptive macroscopic properties of biological systems as the outcome of collective social computation
- Time: 12:05 pm
- Place: 4274 Chamberlin (refreshments will be served)
- Speaker: Jessica Flack, Wisconsin Institute for Discovery
- Abstract: A central problem in evolutionary theory is why life is hierarchically organized. This problem can be decomposed into four somewhat separate issues (1) the causes of the emergence of novel, functionally important spatial and temporal scales, (2) the reification of these scales into new organizational levels, (3) the multi-level selection problem, and (4) transitions to new kinds of individuality. In this talk, I will focus on (1) and (2), using data from an animal society model system to illustrate how adaptive macroscopic properties can arise as many individuals simultaneously coarse-grain over microscopic interactions to reduce uncertainty and tune decision-making strategies.
- Host: Sprott
- No events scheduled
- R. G. Herb Condensed Matter Seminar
- Majorana fermions in vortex lattices
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Rudro Rana Biswas, University of Illinois at Urbana-Champaign
- Abstract: We consider Majorana fermions tunneling between vortices, within an array of such vortices in a 2D chiral p-wave superconductor. We calculate that the tunneling amplitude for Majorana fermions in a pair of vortices is proportional to the sine of half the difference between the global order parameter phases at the two vortices. Using this result we study tight-binding models of Majorana fermions in vortices arranged in a triangular or square lattice. In both cases we find that this phase-tunneling relationship leads to the creation of superlattices where the Majorana fermions form macroscopically degenerate 'flat' bands at zero energy, in addition to other dispersive bands. This finding suggests that in vortex arrays tunneling processes do not change the energies of a finite fraction of Majorana fermions and hence brighten the prospects of topological quantum computing with a large number of Majorana states.
- Host: Perkins
- Astronomy Colloquium
- The Magellanic Stream: Probing the Baryon Cycle in the Galactic Halo
- Time: 3:25 pm
- Place: 4421 Sterling Hall
- Speaker: Andrew Fox, STSci
- Abstract: The inflow of gas onto galaxies is a key driver of their formation and evolution.A prime local example of a gas flow is the Magellanic Stream (MS), a massive tail of material stripped out of the Magellanic Clouds and extending for almost 200 degrees across the Southern sky. The MS appears to be fragmenting and evaporating as it interacts with the hot Galactic corona, and it remains unclear how much of its neutral gas will survive to reach the Galactic disk to fuel future star formation.
I will present recent results from an ongoing observing campaign
on the MS, using UV (HST/COS) and optical (VLT/UVES) spectroscopy,
paying particular attention to the chemical and physical conditions in the gas.
- Host: Bart Wakker
- Graduate Introductory Seminar
- Atomic, Molecular, and Optical Physics
- Time: 5:45 pm
- Place: 2223 Chamberlin Hall
- Speaker: Lawler, Lin, Saffman, Walker, Wehlitz, Yavuz, UW Madison
- Cosmology Journal Club
- An Informal discussion about a broad variety of arXiv papers related to Cosmology
- Time: 12:00 pm
- Place: 5242 Chamberlin Hall
- Abstract: Please visit the following link for more details:
Please feel free to bring your lunch!
If you have questions or comments about this journal club, would like to propose a topic or volunteer to introduce a paper, please email Le Zhang (firstname.lastname@example.org)
- Host: Peter Timbie
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Exploring Majorana landscape: the NEXT generation
- Time: 1:00 pm
- Place: 4274 Chamberlin
- Speaker: Juan JosÃ© GÃ³mez Cadenas, IFIC - Instituto de FÃsica Corpuscular, Valencia, Spain
- Abstract: Neutrinos may be Majorana particles. If so, neutrino less double beta decay processes could be observed by the next generation of bb0nu experiments. I will briefly review the state of the art, then discuss one of the most promising ideas in the field, the use of Hight Pressure Gas Xenon TPC (HPGXe) with electroluminescence gain and optical readout. A 100 kg incarnation of such a device will start operations at the Canfranc Underground Lab in Spain in late 2013 or early 2014. The technology can be extrapolated to 1 ton, and thus lead the exploration of the inverse hierarchy in Majorana landscape.
- Host: Halzen
- Theory Seminar (High Energy/Cosmology)
- Using Singularity for Missing Mass Measurements
- Time: 2:00 pm
- Place: 5280 Chamberlin
- Speaker: Ian-Woo Kim, University of Michigan
- Abstract: We propose a novel generalized method for mass measurements based on the singularity structure of the kinematic phase space that can be applied to any event topology with missing energy. By analyzing the local properties of the observable phase space near a given singularity point, we provide a systematic way to obtain optimized normalized coordinates for the case of interest. Our method subsumes the well-known end-point and transverse mass methods and yields new techniques for studying ``missing particle" events, such as the double chain production of stable neutral particles at the LHC.
- Physics Department Colloquium
- Neutrinos and the Origin of the Elements
- Time: 3:30 pm
- Place: 2241 Chamberlin Hall (coffee at 4:30 pm)
- Speaker: Yong-Zhong Qian, University of Minnesota
- Abstract: Neutrinos are important in driving the expansion of the universe shortly after the big bang and play dynamic roles in supernovae. They also determine the conditions for nucleosynthesis in these two environments. Consequently, big bang and supernova nucleosynthesis is a sensitive probe of the fundamental properties of neutrinos, such as the number of neutrino flavors and the parameters of neutrino oscillations. This talk focuses on the supernova nucleosynthesis probe in view of the recent major advances in experimental studies of neutrino oscillations and in astrophysical observations of elemental abundances. The strong interplay among nuclear, particle physics and astrophysics is emphasized.
- Host: Balantekin & Lawler