Direct Observation of Tunneling and Nonlinear Self-Trapping in a single Bosonic Josephson Junction

TL;DR

This paper reports the first experimental realization of a single bosonic Josephson junction, demonstrating nonlinear tunneling dynamics and macroscopic quantum self-trapping in Bose-Einstein condensates.

Contribution

It provides the first direct observation of nonlinear tunneling and self-trapping effects in a bosonic Josephson junction using in situ measurements.

Findings

Verification of nonlinear tunneling oscillations

Observation of macroscopic quantum self-trapping

Inhibition of large amplitude tunneling oscillations

Abstract

We report on the first realization of a single bosonic Josephson junction, implemented by two weakly linked Bose-Einstein condensates in a double-well potential. In order to fully investigate the nonlinear tunneling dynamics we measure the density distribution in situ and deduce the relative phase between the two condensates from interference fringes. Our results verify the predicted nonlinear generalization of tunneling oscillations in superconducting and superfluid Josephson junctions. Additionally we confirm a novel nonlinear effect known as macroscopic quantum self-trapping, which leads to the inhibition of large amplitude tunneling oscillations.