Transport and macroscopic quantum tunneling of one-dimensional Bose gases in an optical lattice

摘要

In recent experiments of cold atomic gases confined in optical lattices, transport of one-dimensional (1D) Bose gases has been investigated by suddenly displacing the confining potential [1] and using a moving optical lattice [2]. In this work, we discuss the super uidity of 1D Bose gases in optical lattice and especially focus on explaining the experiment of Fertig et al. [1], where unexpectedly strong inhibition of transport was observed [4]. Since mean-field theories fail even qualitatively to describe the transport properties of such 1D Bose gases due to strong quantum uctuations, we use the time-evolving block decimation method [3] to simulate the experiment. We show that the strong inhibition of transport observed in the experiment is attributed to the breakdown of super uid ow accelerated by quantum uctuations. Moreover, we relate the damping of the dipole oscillation to the decay of supercurrents via macroscopic quantum tunneling in a ring optical lattice.