Accurate numerical verification of the instanton method for macroscopic quantum tunneling: Dynamics of phase slips
Ippei Danshita, Anatoli Polkovnikov
We study the quantum dynamics of supercurrents of one-dimensional Bose gases in a ring optical lattice to verify instanton methods applied to coherent macroscopic quantum tunneling (MQT). We directly simulate the real-time quantum dynamics of supercurrents, where a coherent oscillation between two macroscopically distinct current states occurs due to MQT. The tunneling rate extracted from the coherent oscillation is compared with that given by the instanton method. We find that the instanton method is quantitatively accurate when the effective Planck's constant is sufficiently small. We also find phase slips associated with the oscillations.
arXiv:0908.2592•Physical Review B•Sep 3, 2010•15 citations