Continuous Quantum Hypothesis Testing

TL;DR

This paper introduces a comprehensive quantum hypothesis testing framework applicable to various physical systems and measurements, simplifying continuous measurement analysis and enabling efficient quantum detection and experimental validation.

Contribution

It develops a general quantum hypothesis testing theory that applies to any system aspect, including dynamics, and simplifies continuous measurement analysis for practical quantum detection.

Findings

Compact formulae for likelihood ratios in continuous measurements

Efficient computation of likelihood ratios in many scenarios

Application to detecting classical signals and testing quantum models

Abstract

I propose a general quantum hypothesis testing theory that enables one to test hypotheses about any aspect of a physical system, including its dynamics, based on a series of observations. For example, the hypotheses can be about the presence of a weak classical signal continuously coupled to a quantum sensor, or about competing quantum or classical models of the dynamics of a system. This generalization makes the theory useful for quantum detection and experimental tests of quantum mechanics in general. In the case of continuous measurements, the theory is significantly simplified to produce compact formulae for the likelihood ratio, the central quantity in statistical hypothesis testing. The likelihood ratio can then be computed efficiently in many cases of interest. Two potential applications of the theory, namely quantum detection of a classical stochastic waveform and test of harmonic-oscillator energy quantization, are discussed.