Matter-wave bistability in coupled atom-molecule quantum gases

TL;DR

This paper investigates matter-wave bistability in coupled atom-molecule quantum gases, revealing that both Bose and Fermi models exhibit bistable population dynamics due to Kerr nonlinearity, with analogies to quantum optics phenomena.

Contribution

It establishes a novel analogy between atom-molecule quantum gases and quantum optics models, demonstrating bistability arising from Kerr nonlinearity in both Bose and Fermi systems.

Findings

Bistability occurs in molecular population with Feshbach detuning.

Bose model maps to nondegenerate parametric down-conversion.

Fermi model maps to a laser-atom interaction model.

Abstract

We study the matter-wave bistability in coupled atom-molecule quantum gases, in which heteronuclear molecules are created via an interspecies Feshbach resonance involving either two-species Bose or two-species Fermi atoms at zero temperature. We show that the resonant two-channel Bose model is equivalent to the nondegenerate parametric down-conversion in quantum optics, while the corresponding Fermi model can be mapped to a quantum optics model that describes a single-mode laser field interacting with an ensemble of inhomogeneously broadened two-level atoms. Using these analogy and the fact that both models are subject to the Kerr nonlinearity due to the two-body s-wave collisions, we show that under proper conditions, the population in the molecular state in both models can be made to change with the Feshbach detuning in a bistable fashion.