Quantum fidelity decay of classically integrable dynamics with vanishing time averaged perturbation

Abstract

We discuss quantum fidelity decay of classically regular dynamics, in particular for an important special case of vanishing time averaged perturbation operator. We show that quantum fidelity of individual initial states exhibits three different regimes in time: (i) for short times t < t_1 it follows the corresponding classical fidelity, (ii) then it freezes at a constant value - the plateau, (iii) only after much longer time t_2 it again starts to decay. This freezing of fidelity is purely quantum phenomenon and could find applications in improving stability of quantum devices.