Internal Josephson Oscillations for Distinct Momenta Bose-Einstein Condensates

TL;DR

This paper investigates internal Josephson oscillations between atomic and molecular Bose-Einstein condensates in a lattice with gauge fields, revealing regimes of oscillations involving zero and finite momentum condensates, with experimental feasibility.

Contribution

It introduces a model describing Josephson oscillations between zero-momentum and finite-momentum BECs in a lattice with gauge fields, highlighting new oscillation regimes.

Findings

Oscillations between zero-momentum condensates for small flux.

Regime of oscillations involving vortex-carrying finite-momentum condensates.

Experimental detection feasible with Ramsey interference techniques.

Abstract

The internal Josephson oscillations between an atomic Bose-Einstein condensate (BEC) and a molecular one are studied for atoms in a square optical lattice subjected to a staggered gauge field. The system is described by a Bose-Hubbard model with complex and anisotropic hopping parameters that are different for each species, i.e., atoms and molecules. When the flux per plaquette for each species is small, the system oscillates between two conventional zero-momentum condensates. However, there is a regime of parameters in which Josephson oscillations between a vortex-carrying atomic condensate (finite momentum BEC) and a conventional zero-momentum molecular condensate may be realized. The experimental observation of the oscillations between these qualitatively distinct BEC's is possible with state-of-the-art Ramsey interference techniques.