Spin Squeezing and Quantum Correlations

TL;DR

This paper reviews recent advances in the generation and measurement of multiatom states, focusing on spin squeezing and quantum entanglement, and explores their relationship in quantum metrology and information.

Contribution

It provides an overview of quantitative measures of spin squeezing and discusses their intrinsic connection to quantum entanglement in multiqubit systems.

Findings

Spin squeezing relates to uncertainty relations in collective angular momentum.

Quantum entanglement arises from superpositions in multiparticle Hilbert space.

Spin squeezing can serve as an indicator of quantum entanglement.

Abstract

Recent years have witnessed revolutionary improvement in the production, manipulation, characterization and quantification of multiatom (multiqubit) states - because of their promising applications in high precision atomic clocks, atomic interferrometry, quantum metrology and quantum information protocols. In the characterization and quantification of non-classical atomic correlations, two concepts namely, spin squeezing and quantum entanglement emerge. While spin squeezing originates from the uncertainty relation between atomic collective angular momentum operators, entanglement is a peculiar phenomena arising due to superpositions in the multiparticle Hilbert space. Here, we outline different quantitative measures of spin squeezing and discuss the intrinsic relation of spin squeezing with quantum entanglement in multiqubit systems.