Quantum Nucleation of Phase Slips in a 1d Model of a Superfluid

TL;DR

This paper introduces a numerical method to calculate quantum tunneling rates in a 1d superfluid model, focusing on phase slip nucleation during flow past an obstacle, with implications for understanding superfluid decay.

Contribution

It presents a novel numerical approach to find quantum tunneling rates in extended bosonic systems using the Gross-Pitaevskii model, specifically for phase slip nucleation.

Findings

The action for tunneling configurations approaches zero at the classical slip threshold.

The method successfully computes quantum decay rates of metastable superfluid states.

Applications to other quantum processes in superfluids are discussed.

Abstract

We use a 1d model of a superfluid based on the Gross-Pitaevskii Lagrangian to illustrate a general numerical method designed to find quantum tunneling rates in extended bosonic systems. Specifically, we study flow past an obstacle and directly solve the imaginary time dynamics to find the ``bounce'' solution connected with the decay of the metastable laminar state via phase slip nucleation. The action for the tunneling confuguration goes to zero at the threshold (in superfluid velocity) for classical production of these slips. Applications to other processes are briefly discussed.