Quantum Information at the Interface of Light with Atomic Ensembles and Micromechanical Oscillators

TL;DR

This review discusses recent advances in light-matter interfaces involving atomic vapors and mechanical oscillators, highlighting their potential for quantum communication, sensing, and computation.

Contribution

It summarizes new tunable light-matter interactions enabling enhanced quantum protocols and explores interfaces between atomic spins and mechanical oscillators for quantum information.

Findings

Improved entanglement-assisted magnetometry nearing Quantum Cramer-Rao limit

Quantum memory for squeezed light states demonstrated

Heisenberg scaling in cold atom clock experiments

Abstract

This article reviews recent research towards a universal light-matter interface. Such an interface is an important prerequisite for long distance quantum communication, entanglement assisted sensing and measurement, as well as for scalable photonic quantum computation. We review the developments in light-matter interfaces based on room temperature atomic vapors interacting with propagating pulses via the Faraday effect. This interaction has long been used as a tool for quantum nondemolition detections of atomic spins via light. It was discovered recently that this type of light-matter interaction can actually be tuned to realize more general dynamics, enabling better performance of the light-matter interface as well as rendering tasks possible, which were before thought to be impractical. This includes the realization of improved entanglement assisted and backaction evading magnetometry approaching the Quantum Cramer-Rao limit, quantum memory for squeezed states of light and the dissipative generation of entanglement. A separate, but related, experiment on entanglement assisted cold atom clock showing the Heisenberg scaling of precision is described. We also review a possible interface between collective atomic spins with nano- or micromechanical oscillators, providing a link between atomic and solid state physics approaches towards quantum information processing.