Sequential weak measurement

TL;DR

This paper extends weak measurement formalism to sequences of observables, enabling joint property extraction in quantum systems and offering insights into counterfactual quantum computation.

Contribution

It introduces a formalism for sequential weak measurements, allowing joint property analysis of non-commuting observables in quantum systems.

Findings

Allows measurement of joint properties of non-commuting observables

Provides a characterization of counterfactual quantum computation

Enables information extraction with minimal disturbance

Abstract

The notion of weak measurement provides a formalism for extracting information from a quantum system in the limit of vanishing disturbance to its state. Here we extend this formalism to the measurement of sequences of observables. When these observables do not commute, we may obtain information about joint properties of a quantum system that would be forbidden in the usual strong measurement scenario. As an application, we provide a physically compelling characterisation of the notion of counterfactual quantum computation.