Protective Measurement -- a new quantum measurement paradigm: detailed description of the first realisation

TL;DR

This paper details the first experimental realization of protective measurement, a novel quantum measurement method that measures expectation values from a single particle without destroying its state, potentially advancing quantum technologies.

Contribution

It provides the first detailed experimental demonstration of protective measurement, combining weak interactions with state protection to measure expectation values from a single quantum system.

Findings

Successful experimental realization of protective measurement.

Ability to measure expectation values from a single particle.

Potential implications for quantum technology fields.

Abstract

We present a detailed description of the experiment realising for the first time a protective measurement, a novel measurement protocol which combines weak interactions with a ``protection mechanism'' preserving the measured state coherence during the whole measurement process. Furthermore, protective measurement allows finding the expectation value of an observable, i.e. an inherently statistical quantity, by measuring a single particle, without the need of any statistics. This peculiar property, in sharp contrast with the framework of traditional (projective) quantum measurement, might constitute a groundbreaking advance for several quantum technology related fields.