Events at Physics
Events During the Week of January 23rd through January 30th, 2011
- Plasma Physics (Physics/ECE/NE 922) Seminar
- "Ion Energization During Magnetic Reconnection in MST"
- Time: 12:05 pm
- Place: 2241 Chamberlin Hall
- Speaker: Rich Magee, University of Wisconsin/Dept. of Physics/Plasma
- Chaos & Complex Systems Seminar
- "Chaos in Easter Island Ecology"
- Time: 12:00 pm
- Place: 4274 Chamberlin Hall
- Speaker: Clint Sprott, University of Wisconsin/Dept. of Physics/Plasma
- Abstract: Easter Island in the South Pacific, with an area the same as the city of Madison, is one of the most remote inhabited spots in the world, located over 2000 km from its nearest inhabited neighbor. As such, it offers an opportunity to study a relatively simple ecology with possible global implications. Its human population is thought to have grown to a peak of about 10,000 during the millenia leading up to the year 1700, and then to decline to a mere 110 by the year 1877. The usual explanation is that the inhabitants overconsumed the abundant palm trees that were used for cooking, housing, fishing boats, and for transporting the large stone statues for which the island is famous, leading to starvation, war, disease, and possibly cannibalism. In this talk, I will describe some recent simple mathematical models for the rise and fall of their civilization and will show that one of these models has chaotic solutions, not previously known.
This talk is available as a PowerPoint Presentation.
- High Energy Seminar
- New Experiments with Antiprotons
- Time: 3:00 pm
- Place: 4274 Chamberlin
- Speaker: Daniel Kaplan, Illinois Institute of Technology
- Abstract: Fermilab operates the world's most intense antiproton source. Newly
proposed experiments can use those antiprotons either parasitically during
Tevatron Collider running or after the end of the Tevatron Collider program
(currently planned for late 2011). For example, the annihilation of 5 to 8
GeV antiprotons is expected to yield world-leading sensitivities to hyperon
rare decays and CP violation. It could also provide the world's most intense
source of tagged D^0 mesons, and thus the best near-term opportunity to
study charm mixing and, via CP violation, to search for new physics. Other
precision measurements that could be made include properties of the X(3872)
and the charmonium system. An experiment using a Penning trap and an atom
interferometer could make the world's first measurement of the gravitational
force on antimatter. These and other potential measurements using
antiprotons could lead to a broad physics program at Fermilab in the
- Host: Smith
- No events scheduled
- R. G. Herb Condensed Matter Seminar
- Shock waves in cold Fermi atoms
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Alexander Abanov, Stony Brook University
- Abstract: I will discuss a recent experiment performed by James Joseph and John Thomas in Duke University. They experimentally produced a collision between two ultra-cold atomic clouds made out of a unitary Fermi gas. During the collision a very sharp and stable density peak at the center of the trap was formed and subsequently evolved into a box-like shape. We demonstrate that we can model the nonlinear dynamics of this collision using a dimensionally reduced quasi-1D form of hydrodynamic equations of motion. The quasi-1D nonlinear hydrodynamics shows near perfect agreement with the experiment and we see a clear evidence of shock wave formation which is a hallmark of nonlinear physics.
- Host: Andrey Chubukov
- Astronomy Colloquium
- "Toward the Formation of Realistic Disk Galaxies".
- Time: 3:30 pm
- Place: 4421 Sterling Hall
- Speaker: Alyson Brooks, CALTECH
- Abstract: Much progress has been made in recent years in forming realistic disk galaxies in fully cosmological simulations. I will highlight the necessity of both 1) a physically motivated prescription for star formation and feedback and 2) very high numerical resolution to achieve a successful model for the formation of disk galaxies<br>
(including bulgeless dwarf disk galaxies). The resulting simulated galaxies simultaneously match observed disk scaling relations (stellar mass -- metallicity, size -- luminosity, size -- velocity, and velocity -- luminosity) for the first time. Realistic simulated galaxies are the necessary starting point for interpreting observations in light of galaxy formation theory. Hence, I will conclude by highlighting the science enabled by these state-of-the-art simulations.
- Host: Astronomy Department
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- New CMB Polarization Results from QUIET at 43-GHz
- Time: 4:00 pm
- Place: 4274 Chamberlin Hall
- Speaker: Immanuel Buder, University of Chicago
- Abstract: Inflationary cosmology postulates that the Universe underwent a period of accelerated expansion in the first 10^-30 s after the Big Bang. Inflationary models are attractive because they solve outstanding problems in cosmology: the origin of structure, the absence of monopoles, and the horizon and flatness problems. Although inflation is consistent with existing data, the fundamental physics responsible for it is unknown. Cosmic Microwave Background (CMB) measurements promise to verify one of the predictions of inflation: odd-parity polarization modes (B modes).
CMB B modes have not yet been detected. The Q/U Imaging ExperimenT (QUIET) recently reported a measurement of the CMB polarization at 43-GHz (Q band). This is one of the best limits to date on inflationary B modes. Moreover the unique QUIET design leads to the lowest levels of systematic contamination in the inflationary signal reported by any CMB polarization experiment.
I will describe the QUIET instrument, how it mitigates systematic contamination, and results from the first season of Q-band observation. I will also report the status of analysis of the second-season 95-GHz (W-band) data.
- Host: Peter Timbie
- No events scheduled