Entanglement and extreme spin squeezing of unpolarized states

verfasst von: 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.
Organisationseinheit(en): Institut für Quantenoptik
SFB 1227: Designte Quantenzustände der Materie (DQ-mat)
Externe Organisation(en): Universidad del País Vasco (UPV)
Ikerbasque, the Basque Foundation for Science
Hungarian Academy of Sciences
Typ: Artikel
Journal: New Journal of Physics
Band: 19
ISSN: 1367-2630
Publikationsdatum: 20.01.2017
Publikationsstatus: Veröffentlicht
Peer-reviewed: Ja
ASJC Scopus Sachgebiete: Physik und Astronomie (insg.)
Elektronische Version(en): https://doi.org/10.1088/1367-2630/19/1/013027 (Zugang: Offen)

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",
}