Events at Physics |
Events on Thursday, October 31st, 2013
- R. G. Herb Condensed Matter Seminar
- Robust, self-consistent, closed-form tomography of quantum logic gates on a trapped ion qubit
- Time: 10:00 am
- Place: 5310 Chamberlin Hall
- Speaker: John Gamble, Sandia National Laboratory
- Abstract: We introduce and demonstrate experimentally: (1) a framework called "gate set tomography" (GST) for self-consistently characterizing an entire set of quantum logic gates on a black-box quantum device; (2) an explicit closed-form protocol for linear-inversion gate set tomography (LGST), whose reliability is independent of pathologies such as local maxima of the likelihood; and (3) a simple protocol for objectively scoring the accuracy of a tomographic estimate without reference to target gates, based on how well it predicts a set of testing experiments. We use gate set tomography to characterize a set of Clifford-generating gates on a single trapped-ion qubit, and compare the performance of (i) standard process tomography; (ii) linear gate set tomography; and (iii) maximum likelihood gate set tomography. arXiv:1310.4492
- Host: Coppersmith
- Astronomy Colloquium
- The E-Nova Project: A Multi -Wavelength Initiative to Prove the ejecta and Environments of Novae
- Time: 3:30 pm - 5:00 am
- Place: 4421 Sterling Hall
- Speaker: Laura Chomiuk, Michigan State
- Abstract: When imagining a nuclear explosion, we often picture strong, spherical shock waves, like a bomb or supernova; however, nature's most common thermonuclear explosions look nothing like this, showing delayed and multiple phases of mass ejection that can last for months after the nuclear fuel is ignited. These most common explosions are novae---thermonuclear runaways on the surfaces of accreting white dwarfs---and their complexities are best revealed with an intensive multi-wavelength observational program highlighting radio and X-ray data---our E-Nova Project. I will discuss our recent results, featuring observations from the newly-upgraded Karl G. Jansky Very Large Array, and spotlighting sources like the recurrent nova T Pyx (which is challenging our basic assumptions about accretion on white dwarfs) and the four novae that have been detected in gamma rays to date (an emission process that was not predicted and remains an intriguing mystery). The implications for Type Ia supernova progenitors will also be discussed.
- Host: Professor Eric Wilcots