Events at Physics
Events on Thursday, October 6th, 2016
- R. G. Herb Condensed Matter Seminar
- Scaling analysis and instantons for quantum spin tunneling and Quantum Monte Carlo simulations
- Time: 10:00 am
- Place: 5310 Chamerlin Hall
- Speaker: Vadim Smelyanskyi, Google
- Abstract: We will provide an overview of recent results of Google quantum computing team on the role of collective tunneling in quantum annealing algorithm. We will discuss the comparison of theory and experiments performed on DWave machine. We will describe an instantonic calculus for the thermally-assisted tunneling decay rate in a fully connected quantum spin model. We show that the tunneling decay problem can be mapped onto the Kramers escape problem of a classical random dynamical field. This dynamical field is simulated efficiently by Path Integral Quantum Monte Carlo (QMC). We show that the exponential scaling with the number of spins of the quantum tunneling rate and the escape rate of the QMC process are identical. We provide further examples where QMC has quadratic speed up in scaling over quantum tunneling.
- Host: Vavilov
- 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:
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 Amol Upadhye (email@example.com).
- Host: Amol Upadhye
- Astronomy Colloquium
- The Central Molecular Zone of the Galaxy: Dense Molecular Clouds, Massive Stars and Magnetic Fields
- Time: 3:30 pm
- Place: 4421 Sterling Hall, Coffee and Cookies 3:30 pm, Talk at 3:45 PM
- Speaker: Cornelia Lang, University of Iowa, Department of Physics and Astronomy
- Abstract: In addition to harboring a supermassive black hole at its very core, the Galactic Center is one of the most physically extreme environments in the Galaxy. Dense and massive molecular clouds are abundant in this region, yet star formation is not as active as one might expect. In addition, radio observations have revealed a population of synchrotron-emitting filaments that provide insight on the magnetic field strength and configuration in this unique region of the Galaxy. Physical interactions may be occurring at the interfaces of dense molecular clouds and the interstellar magnetic filaments. I will review recent observational results of several unusual molecular clouds and the population of magnetized filaments that stand out in radio continuum images of the Galactic center and discuss the implications for better understanding the astrophysics of this region.
- Host: UW Astronomy Deparment
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- High Energy Neutrinos from pulsar wind nebulae
- Time: 3:30 pm
- Place: 5280 Chamberlin Hall ***Note New Time****
- Speaker: Dafne Guetta, ORT Braude College
- Abstract: Several Pulsar Wind Nebulae (PWN) have been detected in the TeV band in the last years. This TeV emission can be fitted with a purely leptonic model making some assumptions on the Infrared backround around the PWN and on the magnetic field that most of the times is far from its equipartition value. We consider the possibility that part of this emission is due to an hadronic component implying the production of 1-100 TeV neutrinos. The IceCube high-energy neutrino telescope has been collecting data since 2006 and so far no neutrino event has been associated with a PWN. We use the non-detection of neutrinos to constrain the hadronic content of PWN independent of the hadronic model parameters. We also estimate the number of neutrino events expected from these sources in Antares and in KM3NeT and derive the constraints on the hadronic contribution to the TeV emission. Both Antares and KM3NeT have better potential than IceCube to detect neutrinos from PWNs as these sources are galactic.
- Host: Francis Halzen