Events at Physics |
Events During the Week of March 23rd through March 30th, 2014
Monday, March 24th, 2014
- 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:
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
Tuesday, March 25th, 2014
- Chaos & Complex Systems Seminar
- Managing complexity at the molecular scale
- Time: 12:05 pm
- Place: 4274 Chamberlin (refreshments will be served)
- Speaker: Tehshik Yoon, UW Department of Chemistry
- Abstract: Chemical synthesis inflects every aspect of modern life. Everything from the clothes we wear to the food we eat to the medicines that so many of us take on a daily basis benefit from the products of chemical synthesis. Chemistry has been able to have such a profound impact on human life because of chemist's ability to construct complex organic molecules with precisely defined three-dimensional shapes. In this talk, I will attempt to explain what some of the most interesting challenges and opportunities are in contemporary organic synthesis.
- Host: Clint Sprott
Wednesday, March 26th, 2014
- Department Meeting
- Time: 12:15 pm
- Place: 5310 Chamberlin Hall
Thursday, March 27th, 2014
- R. G. Herb Condensed Matter Seminar
- Superconducting qubits and cavities: sidebands and vortices
- Time: 10:00 am
- Place: 5310 Chamberlin Hall
- Speaker: Professor Britton Plourde, Syracuse University
- Abstract: There has been tremendous progress in recent years with the development of superconducting qubits and cavities. I will describe two recent efforts in this area at Syracuse University. We have implemented a frequency-modulated driving technique with asymmetric transmon qubits for generating first-order sideband transitions for the rapid exchange of excitations between qubits and cavities. There are a variety of loss mechanisms that can influence the performance of both superconducting cavities and qubits, including magnetic flux vortices and quasiparticles. We are working on experiments with structures for trapping a single vortex in a superconducting microwave cavity. For certain locations of the vortex in the cavity, we observe a decrease in the microwave loss, which we attribute to a reduction of the quasiparticle density due to interactions with the vortex core.
- Host: McDermott
- Faculty Candidate Seminar
- Radar Detection of HE Neutrinos in the Ice
- Time: 1:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Kael Hanson, Université Libre de Bruxelles
- Abstract: The recent IceCube measurement of an excess of neutrino events in the energy range of 30 TeV to 2 PeV is an extremely interesting result which points to the existence of a detectible neutrino signal from diffuse galactic and extragalactic cosmic ray acceleration sites. The limited data is most compatible with a power law flux with spectral index near -2, consistent with production via Fermi shock acceleration, however the limited dynamic range of the measurement renders a large error in the determination of the behavior of the energy spectrum and future accumulation of statistics in IceCube above a PeV will come slowly. Extensions to the IceCube optical detector array are being designed to increase the effective area by an order of magnitude. Antenna arrays for the detection of extremely high energy neutrinos by their radio emission are also being designed and built, however these facilities would not detect a significant number of neutrinos of this origin but are rather targeted toward the much higher energy cosmogenic neutrino fluxes. This presentation will explore the possibility of detection of PeV scale energy and higher neutrinos using bistatic radars which reflect off of plasmas created in the energetic electromagnetic neutrino-induced cascades in the ice.
- Host: Joynt/Halzen
- Astronomy Colloquium
- Sizing up Kepler's exoplanets with Asteroseismology
- Time: 3:30 pm
- Place: 4421 Sterling Hall
- Speaker: Travis Metcalfe, Space Science Institute
- Abstract: The past two decades have witnessed accelerating progress on one of the most fundamental questions in astronomy: Are we alone in the Universe? Astronomers have already discovered hundreds of planets around distant stars. Some of them are nearly as small as the Earth and orbit in the Goldilocks of their parent star where liquid water can exist. It remains to be seen whether biological signatures of life or evidence of radio communications can be found in these planetary systems. Our current emphasis is to determine how common such planets might be, to find as many of them as possible, and to characterize those which have already been discovered. I will give an overview of NASA's Kepler space telescope, how it searches for planets around distant stars, and how we characterize those planets using the natural vibrations of their suns.
- Host: Robert Lindner
- Van Vleck Lecture
- Application of Orthogonalized Linear Combination of Atomic Orbital Methods to Complex Materials
- Time: 3:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Professor Wai-Yim Ching, Curator’s Professor, University of Missouri-Kansas City
- Abstract: In this lecture, I present the development and application of an ab initio electronic structure method based on density functional theory, the orthogonalized linear combination of atomic orbital (OLCAO) method. The OLCAO method was initially developed at UW-Madison in mid-70s. Over the years, the method has been steadily improved, refined and withstood the test of time, and emerged as an extremely effective computational tool for complex materials. I will present three examples of its recent applications: (1) Densification of a near-perfect continuous random network model of amorphous SiO2 glass (Fig.1); (2) Genomic approach for the mechanical properties and electronic structure in a novel class of layered ternary compounds, the MAX phases (Mn+1AX2) (M = a transition metal, A= mostly Al or other group III, IV, V elements, X = C or N) (Fig.2); (3) Application to biomolecular systems and large proteins such as brome mosaic virus (1js9) (Fig.3). These examples illustrate the versatility of the OLCAO method in addressing specific problems of different material systems in diversified scientific and engineering fields. Further applications and limitations of the method will also be discussed.
- Host: Chun Lin
Friday, March 28th, 2014
- Theory Seminar (High Energy/Cosmology)
- The IceCube Puzzle
- Time: 2:15 pm
- Place: 5280
- Speaker: Markus Ahlers, Wisconsin IceCube Particle Astrophysics Center
- Abstract: Astrophysical neutrinos are unambiguous tracers of hadronic interactions of cosmic rays (CRs) in our Universe. With this in mind, high energy neutrino astronomy has long been anticipated to help uncover the orgin of high energy CRs. The recent detection of a flux of high-energy extra-terrestrial neutrinos by the IceCube Observatory is an important step in this direction. However, the low statistics and angular resolution of the signal makes an identification of the neutrino sources challenging. I will review various scenarios for the IceCube signal, ranging from exotic PeV dark matter decay to the more conventional candiate sources of high energy CRs. I will finally discuss various multi-messenger observations that can help us to solve the IceCube Puzzle.
- Physics Department Colloquium
- Realism and the epistemic view of quantum states
- Time: 3:30 pm
- Place: 2241 Chamberlin Hall (coffee at 4:30 pm)
- Speaker: Terry Rudolph
- Abstract: The idea that quantum states reflect only an observers knowledge/beliefs/information about the world has a long history. The challenge for an advocate of this position, however, is to identify what we can deduce is "really going on'' out there. There seem to three main paths proponents of the epistemic view have followed in trying to extract such a narrative from quantum theory. I will explain how the most naïve such path--that quantum states can be associated with standard (probabilistic) uncertainty about some (arbitrary) real states of the world--is not tenable under some extremely mild assumptions about how any theory of reality must treat independent experiments. I will then overview the other two paths and what I see as the challenges they face.
- Host: Yavuz