DISSIPATIVE TUNNELING IN A SINE-GORDON CHAIN AT HIGH-TEMPERATURES

The dissipative tunnelling in a sine-Gordon chain driven by a weak external bias is investigated with special focus on the quantum-mechanical effects at higher temperatures where thermal activation still dominates over quantum tunnelling. Quantum-mechanical corrections to the nudeation process enhance the rate above its classical value for any intensity of the damping mechanism. However, contrary to the single-particle case, quantum effects enter the result for the nucleation rate in lowest order in h, instead of hz, and it exhibits a nonanalytic dependence on the quantum scale. © 1990 IOP Publishing Ltd.