Events at Physics |
Events During the Week of October 26th through November 2nd, 2014
Monday, October 27th, 2014
- Cosmology Journal Club
- An Informal discussion about a broad variety of arXiv papers related to Cosmology
- Time: 12:15 pm
- Place: 5242 Chamberlin Hall
- Abstract: Please visit the following link for more details:
http://cmb.physics.wisc.edu/journal/index.html
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 (lzhang263@wisc.edu) - Host: Peter Timbie
- Council Meeting
- Time: 4:00 pm
- Place: 2314 Chamberlin (Chair's Conference Room)
Tuesday, October 28th, 2014
- PUBLIC ASTRONOMY WHITFORD LECTURE
- Heart of Darkness
- Time: 12:00 pm - 1:00 pm
- Place: 145 BIRGE HALL
- Speaker: Jeremiah Ostriker, Columbia Universty
- Abstract: Can we unravel the secrets to of the universe and construct a scientific model that is believable? Over the past forty years, we have learned that two little-understood components--dark matter and dark energy--comprise most of the known cosmos, explain the growth of all cosmic structure, and hold the key to the universe's fate. The first of these accelerates the collapse of over-dense lumps and the formation of cosmic structures while the second pushes apart the structures that have formed.
From our early attempts to comprehend the solar system, to current space based exploration of our own galaxy and the realm of the nebulae beyond, to the detection of the primordial fluctuations of energy from which all subsequent structure developed, we will try to both explain the physics and also the history of how the current model of our universe arose and has passed every test hurled at it by the skeptics. Throughout this story, an essential theme is emphasized: how three aspects of rational inquiry--the application of direct measurement and observation, the introduction of mathematical modeling, and the requirement that hypotheses should be testable and verifiable--guide scientific progress and underpin our modern cosmological paradigm. While the resulting model “works” to great precision, it still leaves unanswered some of the most fundamental cosmic questions. We know that a cosmic model with more dark matter than ordinary chemical elements and even more dark energy than dark matter works well – ie matches all of the facts – but we do not know the nature of these dominant dark components.
- Host: Dept of Astronomy
- Chaos & Complex Systems Seminar
- On reactive model-free stock trading in a complex financial market
- Time: 12:05 pm - 1:00 pm
- Place: 4274 Chamberlin Hall (Refreshments will be served)
- Speaker: Bob Barmish, UW Department of Electrical and Computer Engineering
- Abstract: In this seminar, I will describe a new paradigm for stock trading in a complex financial market. The theory does not make use of a predictive model for the time-varying stock price. Instead, based on the use of a feedback control loop, the investment level is dynamically adjusted over time via a "reactive adaptation'' mechanism. In the finance literature, such a scheme falls under the umbrella of "technical analysis.'' After explaining what is meant by technical analysis, I will address a long standing conundrum in finance: Why is it that so many asset managers, hedge funds and individual investors trade stock using technical analysis despite the existence of a significant body of literature claiming that such methods are of questionable worth with little or no theoretical rationale? Whereas existing work on this question by academics and practitioners in finance involves extensive statistical analysis of a trading algorithm via back-testing with historical data, our new feedback-based approach is aimed at providing a theoretical rationale which explains both successes and failures.
- Host: Clint Sprott
- Theory Seminar (High Energy/Cosmology)
- Galactic Center Gamma-ray Excess from a Dark Shower
- Time: 3:00 pm - 4:00 pm
- Place: 5280 Chamberlin Hall
- Speaker: Dean Robinson, University of California, Berkeley
- Abstract: The reported excess of gamma-rays, emitted from an extended region around the galactic center, has a distribution and rate suggestive of an origin in dark matter (DM) annihilations. However, the conventional annihilation channels into standard model (SM) b quarks or tau leptons may be in tension with various experimental constraints on antiproton and positron fluxes. We'll discuss a framework that is free from such constraints. The key idea is that the mediators between the dark matter and the SM are themselves part of a strongly coupled sector. DM annihilation produces a dark hadron shower that in turn decays to photons, but without other significant associated cosmic ray production. We'll also discuss an explicit realization of this framework and its phenomenology.
- Host: Ran Lu
Wednesday, October 29th, 2014
- Department Meeting
- Time: 12:15 pm
- Place: 5310 Chamberlin Hall
Thursday, October 30th, 2014
- R. G. Herb Condensed Matter Seminar
- Quantum Oscillations in Kondo Insulator SmB6
- Time: 10:00 am - 11:00 am
- Place: Chamberlin 5310
- Speaker: Lu Li, University of Michigan
- Abstract: In Kondo insulator samarium hexaboride SmB6, strong correlation and<br>
band hybridization lead to a diverging resistance at low temperature.<br>
The resistance divergence ends at about 3 Kelvin, a behavior recently<br>
demonstrated to arise from the surface conductance. However, questions<br>
remain whether and where a topological surface state exists. Quantum<br>
oscillations have not been observed to map the Fermi surface. We solve<br>
the problem by resolving the Landau Level quantization and Fermi<br>
surface topology using torque magnetometry. The observed angular<br>
dependence of the Fermi surface cross section suggests two-dimensional<br>
surface states on the (101) and (100) plane. Furthermore, similar to<br>
the quantum Hall states for graphene, the tracking of the Landau<br>
Levels in the infinite magnetic field limit points to -1/2, the Berry<br>
phase contribution from the 2D Dirac electronic state. - Host: Vavilov
- Astronomy Colloquium
- The Future of Age: How asteroseismology reveals fundamental properties of Stars like out Sun
- Time: 3:30 pm - 5:00 am
- Place: 4421 Sterling Hall
- Speaker: David Soderblom, Space Telescope Science Institution
- Abstract: Some day fairly soon we can hope to hear an announcement of the signs of life on a planet around another star, and when that happens, our first question will be “How old is that star?” because we will want to place such a discovery in an evolutionary context.But stars do not reveal their ages to us in any direct way and we are left trying to use secondary indicators such as rotation or activity. Asteroseismology offers a real breakthrough in determining stellar ages, particularly for older solar-type stars, and the oscillations detected by Kepler have been especially critical because of their quality and number. In this talk I will present a framework for understanding the problem of stellar age estimation, the limitations encountered with conventional (pre-seismology) methods, how asteroseismology provides constraints on key physical parameters of stars, and what limitations still exist in the problem of estimating stellar ages.
- Graduate Introductory Seminar
- Condensed Matter Experiment and Theory, and Quantum Computing
- Time: 4:30 pm - 5:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Coppersmith, Eriksson, Himpsel, Joynt, McDermott, Onellion, Rzchowski, Saffman, Vavilov, Winokur
Friday, October 31st, 2014
- Theory Seminar (High Energy/Cosmology)
- Evaluating the Thermal WIMP Paradigm in the Light of Anomalies in 2014
- Time: 2:00 pm - 3:00 pm
- Place: 5280 Chamberlin
- Speaker: Kuver Sinha, Syracuse University
- Abstract: I'll look back at some of the anomalies we have seen this year: the "dark matter keV line", the mild, persistent evidence for dark radiation, and the niggling excesses in the charged lepton + jets (leptoquark search) and dilepton (SUSY search) final states at the LHC. I'll discuss prospects for the thermal WIMP paradigm in the light of these anomalies. I'll also discuss the fast-disappearing BICEP anomaly, and whether future polarization experiments will be able to give us, unambiguously, the scale of inflation.
- Host: Ran Lu
- Physics Department Colloquium
- The challenge of fault tolerant quantum computation
- Time: 3:30 pm - 4:30 pm
- Place: 2241 Chamberlin Hall (coffee at 4:30 pm)
- Speaker: Lev Ioffe, Rutgers University
- Abstract: The classical computation is made possible by error correction that allows to completely eliminate errors produced by solid state elements. In contrast to a discrete logical state of a classical computer, its quantum analogue is described the continuous wave function. Nevertheless, the ability to measure the quantum state in different basis allows error correction for quantum computation as well. Both classical and quantum error corrections can be implemented at a hardware level by a proper choice of the Hamiltonian. In this case, the quantum error correction is intimately related to the topological order parameter formed in the quantum systems described by these Hamiltonians.
I discuss simplest examples of the Hamiltonians that provide hardware error corrections by the formation of the topological order parameter and their implementation in the superconducting circuits. I also show that some of these Hamiltonians allow not only the error corrections but also discrete quantum operations, e.g. fault tolerant operations. I will show the experimental data that confirm theoretical predictions. - Host: McDermott