Theory of superfluidity and drag force in the one-dimensional Bose gas

TL;DR

This paper reviews the unique superfluid behavior of the one-dimensional Bose gas, focusing on the drag force and superfluid-insulator transition, with recent experimental and theoretical insights into impurity dynamics and localization effects.

Contribution

It provides a comprehensive analysis of the drag force in 1D Bose gases using linear response theory, connecting superfluidity criteria with dynamical structure factors and disorder effects.

Findings

Quantitative predictions for drag force with various obstacle potentials

Relation between superfluidity breakdown and Anderson localization

Identification of superfluid-insulator transition in disordered systems

Abstract

The one-dimensional Bose gas is an unusual superfluid. In contrast to higher spatial dimensions, the existence of non-classical rotational inertia is not directly linked to the dissipationless motion of infinitesimal impurities. Recently, experimental tests with ultracold atoms have begun and quantitative predictions for the drag force experienced by moving obstacles have become available. This topical review discusses the drag force obtained from linear response theory in relation to Landau's criterion of superfluidity. Based upon improved analytical and numerical understanding of the dynamical structure factor, results for different obstacle potentials are obtained, including single impurities, optical lattices and random potentials generated from speckle patterns. The dynamical breakdown of superfluidity in random potentials is discussed in relation to Anderson localization and the predicted superfluid-insulator transition in these systems.