Superfluidity in Bose-Hubbard circuits

TL;DR

This paper develops a semiclassical theory to understand metastability and chaos in atomtronic superfluid circuits, revealing novel resonance mechanisms distinct from traditional damping effects.

Contribution

It introduces a new theoretical framework describing non-linear resonances in superfluid circuits, differing from classical damping models, and analyzes their impact on system stability.

Findings

Resonances are described by a variant of the Cherry Hamiltonian.

Decay processes depend on the number of sites and particles.

High-dimensional chaos influences metastability regimes.

Abstract

A semiclassical theory is provided for the metastability regime-diagram of atomtronic superfluid circuits. Such circuits typically exhibit high-dimensional chaos; and non-linear resonances that couple the Bogoliubov excitations manifest themselves. Contrary to the expectation these resonances do not originate from the familiar Beliaev and Landau damping terms. Rather, they are described by a variant of the Cherry Hamiltonian of celestial mechanics. Consequently we study the induced decay process, and its dependence on the number of sites and of condensed particles.