Nonreciprocity in Quantum Technology

TL;DR

This paper reviews recent advances in nonreciprocal quantum devices, emphasizing their role in quantum information processing, communication, and sensing, achieved through innovative methods that avoid traditional magnetic biasing.

Contribution

It provides a comprehensive overview of engineered nonreciprocity in quantum systems, highlighting new techniques enabling scalable, integrated, and magnetic-free nonreciprocal devices for quantum technologies.

Findings

Nonreciprocal devices now operate with low loss and no magnetic bias.

Synthetic gauge fields and optomechanics enable scalable nonreciprocity.

Applications include high-fidelity qubit readout and enhanced quantum sensing.

Abstract

Nonreciprocity-the ability to transmit signals in one direction while blocking them in the reverse-has become a powerful resource in quantum technologies, enabling directional amplification, routing of quantum information, and topologically protected quantum states. Recent experimental advances have demonstrated nonreciprocal behavior in low-loss, fully integrated devices operating with weak or no magnetic bias, enabled by synthetic gauge fields, optomechanical interactions, and chiral light-matter coupling. These achievements overcome the limitations of more traditional approaches, making nonreciprocity compatible with superconducting circuits and scalable quantum photonic architectures as well as an integral part of the next generation of modular quantum computers, distributed quantum networks, and precision metrology. Here we highlight the key concepts for engineering nonreciprocity in quantum systems and describe how this functionality can be employed for high-fidelity qubit readout, robust quantum state transfer, and boosting the sensitivity of quantum sensors.