Resolution-enhanced entanglement detection

TL;DR

This paper introduces new entanglement detection criteria for multipartite systems, leveraging Fisher information and squeezing techniques, with practical applicability to current quantum experiments involving trapped ions and atoms.

Contribution

It develops a general family of entanglement criteria that enhance detection sensitivity by utilizing local access and measurement strategies in multipartite quantum systems.

Findings

Fisher information criteria effectively detect entanglement in multipartite systems.

Generalized squeezing criteria provide less strict but experimentally accessible bounds.

Techniques are compatible with existing trapped ion and optical lattice experiments.

Abstract

We formulate a general family of entanglement criteria for multipartite systems. Fisher information criteria compare the sensitivity to unitary rotations with the variances of suitable local observables. Generalized squeezing-type criteria provide lower bounds that are less stringent but only require measurements of second moments. The enhancement due to local access to the individual subsystems is studied in detail for the case of $N$ spin-$1/2$ particles. The discussed techniques can be readily implemented in current experiments with trapped ions in Paul traps and neutral atoms in optical lattices.