Speaker: Ralf Blattmann, University of Augsburg, Germany.

Title: Qubit interference at avoided crossings: The role of driving shape and bath coupling

Abstract:
Sweeping through an avoided crossing with a periodic, large amplitude driving leads to a sequence of transition, where the phase accumulation between transition may result in constructive or destructive interference. This leads to so called Landau-Zener-Stueckelberg-Majorana (LZSM) interference patterns. We derive the structure of the LZSM patterns for a qubit that experiences quantum dissipation and is additionally subjected to time-periodic but otherwise general driving. Numerical as well as analytical results predict a peak structure that depends sensitively on the details of the qubit-bath coupling. The Fourier transforms of the LZSM patterns exhibit arc structures which reflect the shape of the driving, and provide an opportunity to characterize the qubit coherence. We derive an analytical description for the observed structures and numerically determine their decay as a function of dissipation strength and temperature.

Coffee/tea and cake will be served t 14:00