Dissipative Tunnelling 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 nucleation 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 ℏ instead of ℏ 2 , and it exhibits a nonanalytic dependence on the quantum scale.