Quantum Zeno and Anti-Zeno probes of noise correlations in photon polarisation

TL;DR

This paper demonstrates how repeated quantum measurements on a single photon can diagnose non-Markovian noise correlations, revealing regimes associated with quantum Zeno and anti-Zeno effects, thus enabling new noise spectroscopy methods.

Contribution

It introduces a novel experimental approach to diagnose noise correlations using quantum Zeno and anti-Zeno effects in photon polarization measurements.

Findings

Positive correlations lead to quantum Zeno regime.

Negative correlations induce anti-Zeno regime.

Method enables noise spectrum characterization via single-photon probes.

Abstract

We experimentally demonstrate, for the first time, noise diagnostics by repeated quantum measurements. Specifically, we establish the ability of a single photon, subjected to random polarisation noise, to diagnose non-Markovian temporal correlations of such a noise process. In the frequency domain, these noise correlations correspond to colored noise spectra, as opposed to the ones related to Markovian, white noise. Both the noise spectrum and its corresponding temporal correlations are diagnosed by probing the photon by means of frequent, (partially-)selective polarisation measurements. Our main result is the experimental demonstration that noise with positive temporal correlations corresponds to our single photon undergoing a dynamical regime enabled by the quantum Zeno effect (QZE), while noise characterized by negative (anti-) correlations corresponds to regimes associated with the anti-Zeno effect (AZE). This demonstration opens the way to a new kind of noise spectroscopy based on QZE and AZE in photon (or other single-particle) state probing.