Dynamic hysteresis in microscopic systems with static and fluctuating barriers: the pattern of zero and non-zero temperature responses

Abstract

The zero temperature quantum dynamics of a periodically driven particle moving in a bi-stable potential with a static barrier height is shown to sustain hysteresis loops. If the barrier height fluctuates randomly the loop area shrinks and passes through a minimum at a critical frequency of fluctuation (ω⁰_c). At non-zero temperatures, the loop area passes through a maximum at a critical fluctuation frequency (ω^T_c). The overall barrier crossing rates (by tunneling and overbarrier processes) display exactly similar responses. The loop area A reveals a clear maximum as a function of driving frequency (ω_d) at zero temperature while for T>0, two maxima occur on the A-ω plot. The actual crossing rates also display similar resonance like responses to the driving field.