# Quantitative acoustic models for superfluid circuits

## TL;DR

This paper experimentally demonstrates a tunable superfluid oscillator circuit in ultracold atoms, models it as a Helmholtz resonator at low currents, and explores turbulence and dissipation mechanisms at higher currents.

## Contribution

It introduces a simple lumped-element model for superfluid circuits and investigates their behavior across different current regimes, highlighting deviations from existing models.

## Key findings

- Accurate Helmholtz resonator description at low currents
- Turbulent vortex shedding at higher currents
- Deviations from phase-slip model in dissipation mechanisms

## Abstract

We experimentally realize a highly tunable superfluid oscillator circuit in a quantum gas of ultracold atoms and develop and verify a simple lumped-element description of this circuit. At low oscillator currents, we demonstrate that the circuit is accurately described as a Helmholtz resonator, a fundamental element of acoustic circuits. At larger currents, the breakdown of the Helmholtz regime is heralded by a turbulent shedding of vortices and density waves. Although a simple phase-slip model offers qualitative insights into the circuit's resistive behavior, our results indicate deviations from the phase-slip model. A full understanding of the dissipation in superfluid circuits will thus require the development of empirical models of the turbulent dynamics in this system, as have been developed for classical acoustic systems.