Controlling the dynamics of an open many-body quantum system with localized dissipation

TL;DR

This study experimentally explores how localized dissipation affects a Bose-Einstein condensate, revealing a paradoxical decrease in atom loss at high dissipation rates and linking it to the quantum Zeno effect.

Contribution

It demonstrates controlled dissipation in a BEC and uncovers a paradoxical behavior with a theoretical model, advancing open quantum system engineering.

Findings

Losses decrease when dissipation exceeds a critical value

Excellent agreement between experiment and simple theoretical model

Identification of mechanisms behind the paradoxical behavior

Abstract

We experimentally investigate the action of a localized dissipative potential on a macroscopic matter wave, which we implement by shining an electron beam on an atomic Bose-Einstein condensate (BEC). We measure the losses induced by the dissipative potential as a function of the dissipation strength observing a paradoxical behavior when the strength of the dissipation exceeds a critical limit: for an increase of the dissipation rate the number of atoms lost from the BEC becomes lower. We repeat the experiment for different parameters of the electron beam and we compare our results with a simple theoretical model, finding excellent agreement. By monitoring the dynamics induced by the dissipative defect we identify the mechanisms which are responsible for the observed paradoxical behavior. We finally demonstrate the link between our dissipative dynamics and the measurement of the density distribution of the BEC allowing for a generalized definition of the Zeno effect. Due to the high degree of control on every parameter, our system is a promising candidate for the engineering of fully governable open quantum systems.