Microwave-field quantum metrology with inherent robustness against detection losses enabled by Rydberg interactions

TL;DR

This paper demonstrates a quantum sensing method using Rydberg atoms that inherently resists detection losses, achieving high sensitivity through a novel error-prevention protocol involving non-linear lossy channels.

Contribution

It introduces a new quantum metrology protocol leveraging Rydberg interactions to mitigate detection losses, enhancing measurement precision without requiring a quantum computer.

Findings

Achieved a sensitivity of 39 nV/cm/Hz^{−1/2} with Rydberg atoms.

Implemented an error-prevention protocol that introduces a non-linear lossy channel.

Enhanced Fisher information by a factor of 3.3 through the protocol.

Abstract

Quantum sensing and metrology present one of the most promising near-term applications in the field of quantum technologies, with quantum sensors enabling unprecedented precision in measurements of electric, magnetic or gravitational fields and displacements. Experimental loss at the detection stage remains one of the key obstacles to achieving a truly quantum advantage in many practical scenarios. Here, we combine the capabilities of Rydberg atoms to both sense external fields and be used for quantum information processing, thereby largely overcoming the issue of detection losses. While utilising the large dipole moments of Rydberg atoms in an ensemble to achieve a $\SI{39}{\nV\per\cm \hertz\tothe{-1/2}}$ sensitivity, we employ inter-atomic dipolar interactions to take advantage of an error-prevention protocol that protects information against conventional losses at the detection stage. Counterintuitively, the protocol's idea is based on introducing an additional non-linear, lossy quantum channel, which results in a 3.3-fold enhancement of Fisher information. The presented results pave the way for broader adoption of quantum-information-inspired enhancements enabled by intrinsic interactions present in a sensor system, and more broadly in practical quantum metrology and communication, without the need for a general-purpose quantum computer.