Cavity-Mediated Collective Momentum-Exchange Interactions

TL;DR

This paper demonstrates for the first time momentum-exchange interactions mediated by a cavity, enabling collective quantum effects, entanglement, and potential simulations of complex physical phenomena in matter-wave interferometry.

Contribution

It introduces a novel cavity-mediated momentum-exchange interaction in atomic ensembles, expanding quantum simulation and sensing capabilities.

Findings

Observation of all-to-all Ising-like interactions

Emergence of a many-body energy gap

Suppression of Doppler dephasing

Abstract

Quantum simulation and sensing hold great promise for providing new insights into nature, from understanding complex interacting systems to searching for undiscovered physics. Large ensembles of laser-cooled atoms interacting via infinite-range photon mediated interactions are a powerful platform for both endeavours. Here, we realize for the first time momentum-exchange interactions in which atoms exchange their momentum states via collective emission and absorption of photons from a common cavity mode. The momentum-exchange interaction leads to an observed all-to-all Ising-like interaction in a matter-wave interferometer, which is useful for entanglement generation. A many-body energy gap also emerges, effectively binding interferometer matter-wave packets together to suppress Doppler dephasing, akin to M\"ossbauer spectroscopy. The tunable momentum-exchange interaction provides a new capability for quantum interaction-enhanced matter-wave interferometry and for realizing exotic behaviors including simulations of superconductors and dynamical gauge fields.