Decay of Superflow Confined in Thin Torus: Quantum Nucleation of Phase Slips
Munehiro Nishida, Susumu Kurihara
Abstract
The quantum nucleation of phase slips in neutral superfluids confined in a thin torus is investigated by means of the collective coordinate method. We have devised, with numerical justification, a certain collective coordinate to describe the quantum nucleation process of a phase slip. Considering the quantum fluctuation around the local minimum of the action, we calculate the effective mass of the phase slip. Due to the coherence of the condensate throughout the torus, the effective mass is proportional to the circumference L of the torus, and the decay rate has a strong exponential L-dependence. 03.75.Fi, 05.30.Jp, 64.60.Qb, 67.40.Fd, 67.40.Hf Typeset using REVTEX 1 The circulation of superflow in a macroscopic torus container is quantized. However, it has been pointed out that the quantized circulation can decay via the thermal nucleation of phase slips in the case of very narrow torus, or extremely thin superconducting wires [1–4]. If the temperature is low enough, it is probable that the nucleation due to the macroscopic