Diode for Bose-Einstein condensates

TL;DR

This paper proposes a novel diode mechanism for Bose-Einstein condensates using cavity-induced dissipation, avoiding heating and decoherence associated with atomic decay, and demonstrating high efficiency with realistic parameters.

Contribution

It introduces a cavity-mediated dissipation scheme for atom diodes in Bose-Einstein condensates, eliminating the need for atomic decay and reducing decoherence.

Findings

High efficiency of the diode achieved with experimental parameters

Dissipation acts via cavity photon losses, not atomic decay

Method reduces heating and decoherence in condensates

Abstract

Given a quantum state at some instant of time t, the underlying system Hamiltonian can not only predict how the state will evolve, but also the history of the state prior to t. Thereby, in order to have a directed motion, like in a diode, some sort of irreversibility must be considered. For the atom diode, this has been achieved by spontaneous decay of excited atomic levels. For an atomic condensate, it is clear, however, that such decay will cause both heating and decoherence of the condensate. To overcome this complication we introduce a different setup where the dissipation does not act directly on the atoms. The excited atoms are stimulatedly driven back to the ground state by exciting a cavity mode, which in return decays to the vacuum via photon losses. The efficiency of the method utilizing experimental parameters is shown to be almost perfect within large parameter regimes.