Interaction-induced dissipative quantum phase transition in a head-to-tail atomic Josephson junction

TL;DR

This paper predicts a dissipative quantum phase transition in a head-to-tail Bose Josephson junction driven by interatomic interactions, enabling observation without synthetic dissipation and revealing an interaction-controlled insulating phase.

Contribution

It introduces a novel dissipative phase transition mechanism in atomic Josephson junctions driven by intrinsic momentum coupling, expanding understanding of quantum phase transitions in cold atom systems.

Findings

Interaction strength acts as a damping parameter.

Insulating phase emerges with increased repulsive interactions.

Robust phase transition observed without synthetic dissipation.

Abstract

We propose a dissipative phase transition in a head-to-tail Bose Josephson junction. The quantum phase transition has the same origin as the one in a resistively shunted Josephson junction, but the intrinsic momentum coupling between the Josephson mode and the bath modes enables us to observe the dissipative phase transition without any synthetic dissipation. We show that the interatomic interaction strength plays the role of the damping parameter. Consequently, in contrast to a resistively shunted Josephson circuit, the Bose Josephson junction can exhibit an insulating phase in a wider parameter region by increasing the repulsive interaction strength, which is robust against nonperturbative effects. We argue that tight transverse confinement of the quasi-one-dimensional atomic gas allows us to reach the insulating phase.