Sub-shot-noise quantum metrology with entangled identical particles

TL;DR

This paper redefines separability for identical particles using commuting subalgebras, extending quantum Fisher information applications in quantum metrology to better understand sub-shot-noise measurement precision.

Contribution

It introduces a new definition of separability for identical particles and generalizes quantum Fisher information results for quantum metrology.

Findings

Redefinition of separability using commuting subalgebras

Generalization of quantum Fisher information in this context

Physical reinterpretation of quantum metrology results

Abstract

The usual notion of separability has to be reconsidered when applied to states describing identical particles. A definition of separability not related to any a priori Hilbert space tensor product structure is needed: this can be given in terms of commuting subalgebras of observables. Accordingly, the results concerning the use of the quantum Fisher information in quantum metrology are generalized and physically reinterpreted.