Dynamically entangled oscillating state in a Bose gas with an attractive polaron

TL;DR

This paper investigates the out-of-equilibrium dynamics of an impurity in a one-dimensional Bose gas, revealing a long-lived oscillating state caused by transient localization of a depletion cloud, with potential for experimental observation.

Contribution

It introduces the concept of a dynamically entangled oscillating state in a Bose gas with an attractive polaron, highlighting a novel relaxation mechanism and long-lived oscillations.

Findings

Impurity exhibits undamped velocity oscillations before reaching equilibrium.

The lifetime of oscillations increases with impurity-boson coupling strength.

Transient localization of a boson depletion cloud causes the oscillating state.

Abstract

We study the out-of-equilibrium dynamics of an attractively interacting impurity suddenly immersed with a nonzero initial velocity into a system of one-dimensional weakly interacting homogeneous bosons. We uncover and characterize different dynamical regimes in the parameter space. Especially interesting is the relaxation of a fast impurity with a mass close to or exceeding the critical one, where the impurity exhibits undamped temporal long-lived velocity oscillations before reaching a stationary state. The underlying mechanism is the transient localization of a boson depletion cloud near the impurity, that oscillates around the boson density peak situated at the impurity position. The lifetime of this entangled oscillating state increases with the absolute value of the impurity-boson coupling. Cold atomic gases provide an ideal playground where this phenomenon can be probed.