Entanglement and extreme spin squeezing of unpolarized states

authored by: Giuseppe Vitagliano, Iagoba Apellaniz, Matthias Kleinmann, Bernd Lücke, Carsten Klempt, Géza Tóth
Abstract: We present criteria to detect the depth of entanglement in macroscopic ensembles of spin-j particles using the variance and second moments of the collective spin components. The class of states detected goes beyond traditional spin-squeezed states by including Dicke states and other unpolarized states. The criteria derived are easy to evaluate numerically even for systems of very many particles and outperform past approaches, especially in practical situations where noise is present. We also derive analytic lower bounds based on the linearization of our criteria, which make it possible to define spin-squeezing parameters for Dicke states. In addition, we obtain spin squeezing parameters also from the condition derived in (Sørensen and Mølmer 2001 Phys. Rev. Lett. 86 4431). We also extend our results to systems with fluctuating number of particles.
Organisation(s): Institute of Quantum Optics
CRC 1227 Designed Quantum States of Matter (DQ-mat)
External Organisation(s): University of the Basque Country
Ikerbasque, the Basque Foundation for Science
Hungarian Academy of Sciences
Type: Article
Journal: New Journal of Physics
Volume: 19
ISSN: 1367-2630
Publication date: 20.01.2017
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Physics and Astronomy(all)
Electronic version(s): https://doi.org/10.1088/1367-2630/19/1/013027 (Access: Open)

BibTeX

@article{c1d2cc9f20fe4153bf193a3914ef2552,
title = "Entanglement and extreme spin squeezing of unpolarized states",
abstract = "We present criteria to detect the depth of entanglement in macroscopic ensembles of spin-j particles using the variance and second moments of the collective spin components. The class of states detected goes beyond traditional spin-squeezed states by including Dicke states and other unpolarized states. The criteria derived are easy to evaluate numerically even for systems of very many particles and outperform past approaches, especially in practical situations where noise is present. We also derive analytic lower bounds based on the linearization of our criteria, which make it possible to define spin-squeezing parameters for Dicke states. In addition, we obtain spin squeezing parameters also from the condition derived in (S{\o}rensen and M{\o}lmer 2001 Phys. Rev. Lett. 86 4431). We also extend our results to systems with fluctuating number of particles.",
keywords = "Dicke states, entanglement detection, quantum entanglement, spin squeezing",
author = "Giuseppe Vitagliano and Iagoba Apellaniz and Matthias Kleinmann and Bernd L{\"u}cke and Carsten Klempt and G{\'e}za T{\'o}th",
year = "2017",
month = jan,
day = "20",
doi = "10.1088/1367-2630/19/1/013027",
language = "English",
volume = "19",
journal = "New Journal of Physics",
issn = "1367-2630",
publisher = "IOP Publishing Ltd.",
number = "1",
}