Realization of tunnel barriers for matter waves using spatial gaps

TL;DR

This paper demonstrates how spatially varying optical lattices can create tunable tunnel barriers for matter waves, enabling control over trapping, oscillation, and tunneling of Bose-Einstein Condensates in a cavity.

Contribution

It introduces a method to generate and control matter wave tunnel barriers using spatial gaps in an optical lattice with a smooth envelope.

Findings

Observation of wave packet oscillations in a matter wave cavity.

Demonstration of tunneling for specific velocity classes.

Ability to synchronize and shape tunneling properties via envelope design.

Abstract

We experimentally demonstrate the trapping of a propagating Bose-Einstein Condensate in a Bragg cavity produced by an attractive optical lattice with a smooth envelope. As a consequence of the envelope, the band gaps become position-dependent and act as mirrors of finite and velocity-dependent reflectivity. We directly observe both the oscillations of the wave packet bouncing in the cavity provided by these spatial gaps and the tunneling out for narrow classes of velocity. Synchronization of different classes of velocity can be achieved by proper shaping of the envelope. This technique can generate single or multiple tunnel barriers for matter waves with a tunable transmission probability, equivalent to a standard barrier of submicron size.