Sensor Based on Extending the Concept of Fidelity to Classical Waves

TL;DR

This paper introduces a novel remote sensing method using classical waves that applies quantum fidelity concepts, leveraging time-reversal invariance and reciprocity to detect small perturbations with high sensitivity.

Contribution

It extends the quantum fidelity loss concept to classical wave systems, demonstrating a new sensor scheme that enhances sensitivity through exponential amplification and time-reversal techniques.

Findings

Successfully measures small perturbations remotely.

Uses classical wave analog of Loschmidt echo.

Employs exponential amplification to improve sensitivity.

Abstract

We propose and demonstrate a remote sensor scheme by applying the quantum mechanical concept of fidelity loss to classical waves. The sensor makes explicit use of time-reversal invariance and spatial reciprocity in a wave chaotic system to sensitively and remotely measure the presence of small perturbations. The loss of fidelity is measured through a classical wave-analog of the Loschmidt echo by employing a single-channel time-reversal mirror to rebroadcast a probe signal into the perturbed system. We also introduce the use of exponential amplification of the probe signal to partially overcome the effects of propagation losses and to vary the sensitivity.