Non-Hermitian matter wave mixing in Bose Einstein condensates: dissipation induced amplification

TL;DR

This paper demonstrates how engineered non-Hermitian dissipation in Bose-Einstein condensates enables matter-wave amplification via four-wave mixing, overcoming energy mismatch constraints present in Hermitian systems, and explores complex nonlinear dynamics in higher dimensions.

Contribution

It introduces a method to achieve matter-wave amplification through momentum-dependent dissipation, a process forbidden in Hermitian systems, and proposes a physical realization for this dissipation engineering.

Findings

Achieved matter-wave amplification via non-Hermitian dissipation.

Observed rich nonlinear dynamics in higher-dimensional condensates.

Proposed a practical scheme for momentum-dependent atomic loss control.

Abstract

We investigate the nonlinear scattering dynamics in interacting atomic Bose-Einstein condensates under non-Hermitian dissipative conditions. We show that by carefully engineering a momentum-dependent atomic loss profile one can achieve matter-wave amplification through four wave mixing in a one-dimensional quasi free-space setup - a process that is forbidden in the counterpart Hermitian systems due to energy mismatch. Additionally, we show that similar effects lead to rich nonlinear dynamics in higher dimensions. Finally, we propose a physical realization for selectively tailoring the momentum-dependent atomic dissipation. Our strategy is based on a two step process: (i) exciting atoms to narrow Rydberg- or metastable excited states, and (ii) introducing loss through recoil; all while leaving the bulk condensate intact due to protection by quantum interference.