"Beyond Planck-Einstein quanta: Amplitude-driven quantum excitation"

Wen Shen: T. P. Devereaux, and J. K. Freericks; Phys. Rev. B , 11/04/14.

Additional Authors: T. P. Devereaux, and J. K. Freericks


Linear-response quantum excitation is proportional to the amplitude of the field, with the energy of the excitation given by the driving frequency. As the amplitude is increased, there is a crossover, where the excitation energy is governed by the amplitude of the driving field, not its frequency. As the amplitude is increased even further, then complex quantum oscillations develop. We illustrate this phenomena with the exact solution of the simplest model of a charge-density-wave insulator driven by a spatially uniform time-dependent electric field. The driving by the field can be mapped onto a series of Landau-Zener problems, but with a complex, nonmonochromatic drive that varies for each momentum point in the reduced Brillouin zone.