Entanglement-Enhanced Sensing in a Lossy and Noisy Environment

TLDR

Nonclassical states enable quantum metrology with sensitivity gains over classical schemes, yet loss and noise rapidly degrade their advantages. The study aims to experimentally demonstrate an entanglement‑enhanced sensing system that remains robust against quantum decoherence. The experiment achieved a 20 % signal‑to‑noise ratio improvement over the optimal classical scheme under 14 dB loss and a noise background 75 dB stronger than the returned probe, indicating that practical quantum‑sensing technology can be realized.

Abstract

Nonclassical states are essential for optics-based quantum information processing, but their fragility limits their utility for practical scenarios in which loss and noise inevitably degrade, if not destroy, nonclassicality. Exploiting nonclassical states in quantum metrology yields sensitivity advantages over all classical schemes delivering the same energy per measurement interval to the sample being probed. These enhancements, almost without exception, are severely diminished by quantum decoherence. Here, we experimentally demonstrate an entanglement-enhanced sensing system that is resilient to quantum decoherence. We employ entanglement to realize a 20% signal-to-noise ratio improvement over the optimum classical scheme in an entanglement-breaking environment plagued by 14 dB of loss and a noise background 75 dB stronger than the returned probe light. Our result suggests that advantageous quantum-sensing technology could be developed for practical situations.