Ghost imaging as loss estimation: Quantum versus classical schemes

TL;DR

This paper compares quantum and classical ghost spectrometers for estimating filter transmittivity, demonstrating that quantum schemes can offer advantages depending on specific parameters and the number of frequency modes analyzed.

Contribution

It provides the first metrological comparison between quantum and classical ghost spectrometers for spectral analysis tasks.

Findings

Quantum advantage depends on transmittivity and frequency modes.

Quantum schemes outperform classical in certain parameter regimes.

The analysis highlights conditions for optimal quantum metrological performance.

Abstract

Frequency correlations are a versatile and powerful tool which can be exploited to perform spectral analysis of objects whose direct measurement might be unfeasible. This is achieved through a so-called ghost spectrometer, that can be implemented with quantum and classical resources alike. While there are some known advantages associated to either choice, an analysis of their metrological capabilities has not yet been performed. Here we report on the metrological comparison between a quantum and a classical ghost spectrometer. We perform the estimation of the transmittivity of a bandpass filter using frequency-entangled photon pairs. Our results show that a quantum advantage is achievable, depending on the values of the transmittivity and on the number of frequency modes analyzed.