Relaxation to a Phase-Locked Equilibrium State in a One-Dimensional Bosonic Josephson Junction

Marine Pigneur, Tarik Berrada, Marie Bonneau, Thorsten Schumm, Eugene Demler, and Jörg Schmiedmayer

Phys. Rev. Lett. 120, 173601 – Published 27 April 2018

Abstract

We present an experimental study on the nonequilibrium tunnel dynamics of two coupled one-dimensional Bose-Einstein quasicondensates deep in the Josephson regime. Josephson oscillations are initiated by splitting a single one-dimensional condensate and imprinting a relative phase between the superfluids. Regardless of the initial state and experimental parameters, the dynamics of the relative phase and atom number imbalance shows a relaxation to a phase-locked steady state. The latter is characterized by a high phase coherence and reduced fluctuations with respect to the initial state. We propose an empirical model based on the analogy with the anharmonic oscillator to describe the effect of various experimental parameters. A microscopic theory compatible with our observations is still missing.

Received 17 November 2017

DOI:https://doi.org/10.1103/PhysRevLett.120.173601

Physics Subject Headings (PhySH)

Atom optics Bose gases Bose-Einstein condensates Cold atoms & matter waves Decoherence in quantum gases Quantum optics

Atomic, Molecular & Optical

Authors & Affiliations

Marine Pigneur¹, Tarik Berrada¹, Marie Bonneau¹, Thorsten Schumm¹, Eugene Demler², and Jörg Schmiedmayer^1,*

¹Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna, Austria
²Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA