The role of interaction in matter wave optics with motional states

TL;DR

This paper explores how intrinsic interactions in ultracold quantum gases transform matter-wave optics from a linear, single-particle phenomenon into a nonlinear regime, enabling new quantum technologies and affecting interference and coherence.

Contribution

It provides a comprehensive overview of the nonlinear effects of interactions in matter-wave optics and demonstrates their potential for advancing quantum technologies.

Findings

Interactions cause nonlinear diffraction and momentum distributions.

Interference contrast can degrade or collapse due to interactions.

Interactions enable squeezing and entanglement for enhanced sensitivities.

Abstract

Matter-wave optics is often viewed as a linear analogue of photonics, where noninteracting particles are coherently split, diffracted, and recombined, and interference arises from single-particle coherence. In ultracold quantum gases, however, interactions are intrinsic and can rival or exceed kinetic and optical energy scales. This drives matter-wave optics into a nonlinear regime: diffraction and momentum distributions become interaction-dependent, interference contrast degrades or collapses, and revival dynamics appear. In the mean time, interactions can generate squeezing and entanglement, enabling sensitivities beyond the standard quantum limit. We showcase representative examples - covering diffraction, splitting, and interferometry - that illustrate how interactions reshape the basic elements of matter-wave optics and open new opportunities for nonlinear quantum technologies.