Collective atomic recoil motion in short-pulse multi-matter-optical wave mixing

TL;DR

This paper develops an analytical theory for short-pulse matter-wave superradiant scattering, revealing the roles of Bragg resonance, propagation gain, and ground state depletion in the scattering dynamics.

Contribution

It introduces a perturbation theory that explains the asymmetry, gain, and front-edge effects in short-pulse matter-wave superradiance, highlighting the impact of excitation rate and detuning.

Findings

Scattering occurs mainly at the condensate end where the field is strongest.

Propagation gain is minimal, and Bragg resonance is ineffective.

Ground state depletion causes front-edge steepening and peak shifting.

Abstract

An analytical perturbation theory of short-pulse, matter-wave superradiant scatterings is presented. We show that Bragg resonant enhancement is incapacitated and both positive and negative order scatterings contribute equally. We further show that propagation gain is small and scattering events primarily occur at the end of the condensate where the generated field has maximum strength, thereby explaining the apparent ``asymmetry" in the scattered components with respect to the condensate center. In addition, the generated field travels near the speed of light in a vacuum, resulting in significant spontaneous emission when the one-photon detuning is not sufficiently large. Finally, we show that when the excitation rate increases, the generated-field front-edge-steepening and peak forward-shifting effects are due to depletion of the ground state matter wave.