Seminar

Monday, October 29, 2012 2:30 pm - 3:25 pm EDT (GMT -04:00)

Dr. Umesh Vazirani: Certifiable Quantum Dice

Dr. Umesh Vazirani, University of California, Berkeley

Abstract

PLEASE NOTE THE NEW COLLOQUIUM TIME AND LOCATION IN QNC.

Is it possible to certify that the n-bit output of a physical random
number generator is "really random"? In the classical World this seems
impossible.

Monday, October 22, 2012 12:30 pm - 1:30 pm EDT (GMT -04:00)

Patryk Gumann: Nuclear Spin Polarization of low concentration of 31-P in Silicon

Patryk Gumann, IQC

Abstract

Nuclear magnetic resonance (NMR) signal of phosphorus donors ($^{31}$P) in a single crystal of silicon, concentration 6 x 10$^{15}$ cc$^{-1}$ has been measured. The obtained polarization is larger than the expected thermal equilibrium polarization within the time scale of the experiment. A 13 sec build up time a probable nonequilibrium Overhauser mechanism, driven by 1047 nm light irradiation. This polarization is reached a temperature of 4.2 K and a magnetic field of 9.4 T.

Thursday, October 4, 2012 12:00 pm - 1:00 pm EDT (GMT -04:00)

Tobias Moroder: Detection of systematic errors in quantum experiments

Abstract

When systematic errors are ignored in an experiment, the subsequent analysis of its results becomes questionable. We develop tests to identify systematic errors in experiments where only a finite amount of data is recorded and apply these tests to tomographic data taken in an ion-trap experiment. We put particular emphasis on quantum state tomography and present two detection methods: the first employs linear inequalities while the second is based on the generalized likelihood ratio.