Non-Hermitian sensing in the absence of exceptional points

Abstract

Open systems possess unique potentials in high-precision sensing, yet the majority of previous studies rely on the spectral singularities known as exceptional points. Here we theoretically propose and experimentally demonstrate universal non-Hermitian sensing in the absence of exceptional points. The scheme makes use of the intrinsic sensitivity of a non-Hermitian probe to weak external fields, which can be understood as the direct consequence of non-Hermiticity. We confirm the basic mechanism by simulating the sensor-field dynamics using photon interferometry, and, as a concrete example, demonstrate the enhanced sensing of signals encoded in the setting angle of a wave plate. While the sensitivity of the probe is ultimately limited by the measurement noise, we find the non-Hermitian sensor showing superior performance under background noises that cannot be suppressed through repetitive measurements. Our experiment opens the avenue of enhanced sensing without exceptional points, complementing existing efforts aimed at harnessing the unique features of open systems.

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Cited by in corpus (10)

• Review: Quantum Metrology and Sensing with Many-Body Systems
• Non-equilibrium dynamics of localization phase transition in the non-Hermitian Disorder-Aubry-André model
• Achieving the Quantum Fisher Information Bound in Pseudo-Hermitian Sensors
• Quantum sensing with ultracold simulators in lattice and ensemble systems: a review
• High-Order Perfect Absorption in the Absence of Exceptional Point
• Robustness of entanglement in a non-Hermitian cavity-optomechanical system even away from exceptional points
• Unified Bulk-Entanglement Correspondence in Non-Hermitian Systems
• Noisy Stark probes as quantum-enhanced sensors
• Impact of noise on nonlinear-exceptional-point-based sensors
• Enhancement of quantum sensing in a dissipatively coupled two-mode system