Events at Physics
Events on Thursday, April 4th, 2019
- R. G. Herb Condensed Matter Seminar
- Quantum Advantage for Annealing
- Time: 10:00 am
- Place: 5310 Chamberlin Hall
- Speaker: Dr. David Ferguson, Northrop Grumman
- Abstract: Analog annealing using superconducting circuits is a leading candidate to establish a quantum advantage for computing problems of application interest. This seminar will discuss some recent research thrusts in quantum annealing. The first topic will delve into new methods to extract Pauli Hamiltonians using a variant of Bravyi’s Schrieffer-Wolff technique. While this method has many compelling advantages, it also generates non-trivial holonomy of the Hilbert space over the control parameter manifold. This path dependence of the effective Hamiltonian presents both challenges and opportunities for analog control of annealing systems. The next topic builds on this framework to facilitate a direct comparison between quantum and classical models of superconducting circuits using phase space techniques which enable a clear definition of a “Quantum Advantage for Annealing.” Finally, looking to future capabilities, a definition of non-stoquasticity will be presented along with an explanation of why it is relevant for quantum annealing, why typical superconducting qubits don’t have it, and what sort of design changes are necessary to engineer qubits that are simultaneously capable of annealing and generating strong non-stoquastic interactions.
- Host: Vavilov
- Cosmology Journal Club
- Time: 12:00 pm
- Place: 5242 Chamberlin Hall
- Abstract: Please visit the following link for more details:
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 Ross Cawthon (firstname.lastname@example.org) and Santanu Das (email@example.com).
- Astronomy Colloquium
- "Science with a Complete Catalog of Galactic HII Regions"
- Time: 3:30 pm
- Place: 4421 Sterling Hall, Coffee and cookies 3:30 PM, Talk begins 3:45 PM
- Speaker: Loren Anderson, West Virginia University
- Abstract: HII regions are the signature of ongoing high-mass star formation, and are key to understanding star formation and feedback. Modern mid-infrared surveys have for the first time enabled a complete census of Galactic HII regions, and with such a census we can get a global view of high-mass star formation in the Milky Way. We found that all HII regions have the same mid-infrared morphology of ~20um emission surrounded by ~10um emission. The former is largely due to small grains scholastically heated in the HII region plasma and the latter is mostly caused by emission from polycyclic aromatic hydrocarbons. We used mid-infrared survey data to create a catalog of all objects sharing this morphology in the Galaxy, the "WISE Catalog of Galactic HII Regions." This catalog has over 8000 entries, ~2000 of which are known to be HII regions, ~2000 of which are HII region candidates with radio continuum emission from ionized gas, and ~4000 of which are radio-quiet candidates. Radio recombination line observations can turn HII region candidates into known regions, and radio continuum observations can turn radio quiet candidates into candidates. I will detail our efforts on these two fronts, which together have allowed us to determine the Galactic locations of a large number of HII regions and to estimate the overall HII region population.
Over large portions of the Milky Way, the WISE catalog is now statistically complete for all HII regions ionized by single O-stars. With such a catalog, we can begin to examine the overall Galactic HII region population, and to compare massive star formation in the Milky Way with that of external galaxies. Our current investigations include the z-distribution of massive star formation regions and the Sun's height above the midplane, the form Galactic HII region luminosity function, massive star formation in the far outer Galaxy, the Galactic electron temperature gradient, a strange cluster of HII regions near to the Galactic center, the distribution of ionized gas in the inner Galaxy, and the luminosity and star formation rate of the Milky Way.
- Host: Robert Benjamin