Quantum multimode model of elastic scattering from Bose Einstein condensates

TL;DR

This paper develops an analytic quantum multimode model for elastic scattering in Bose-Einstein condensates, capturing incoherent scattering, bosonic enhancement, and the statistics of scattered atoms beyond mean field approximation.

Contribution

It introduces a novel analytic model that incorporates incoherent scattering and bosonic enhancement effects in BECs, extending beyond mean field approaches.

Findings

Identifies conditions for bosonic enhancement in scattering.

Calculates mode occupation dynamics.

Derives full statistics of scattered atoms.

Abstract

Mean field approximation treats only coherent aspects of the evolution of a Bose Einstein condensate. However, in many experiments some atoms scatter out of the condensate. We study an analytic model of two counter-propagating atomic Gaussian wavepackets incorporating dynamics of incoherent scattering processes. Within the model we can treat processes of elastic collision of atoms into the initially empty modes, and observe how, with growing occupation, the bosonic enhancement is slowly kicking in. A condition for bosonic enhancement effect is found in terms of relevant parameters. Scattered atoms form a squeezed state that can be viewed as a multi-component condensate. Not only are we able to calculate the dynamics of mode occupation, but also the full statistics of scattered atoms.