Interaction-induced anomalous transport behavior in one dimensional optical lattice

TL;DR

This paper investigates how impurity atoms in a strongly interacting 1D Bose gas can spontaneously move against gravity due to interaction effects, revealing novel transport phenomena through numerical simulations.

Contribution

It demonstrates interaction-induced anomalous upward transport of impurities in a 1D Bose gas under gravity, linking it to repulsive bound pairs and exploring various parameters.

Findings

Impurity atoms can propagate upwards against gravity due to interactions.

The phenomenon is connected to the formation of repulsive bound pairs.

Transport behavior depends on interaction strength and gravity gradient.

Abstract

The non-equilibrium dynamics of spin impurity atoms in a strongly interacting one-dimensional (1D) Bose gas under the gravity field is studied. We show that due to the non-equilibrium preparation of the initial state as well as the interaction between the impurity atoms and other bosons, a counterintuitive phenomenon may emerge: the impurity atoms could propagate upwards automatically in the gravity field . The effects of the strength of interaction, the gradient of the gravity field, as well as the different configurations of the initial state are investigated by studying the time-dependent evolution of the 1D strongly interacting bosonic system using time-evolving block decimation (TEBD) method. A profound connection between this counterintuitive phenomenon and the repulsive bound pair is also revealed.