Entanglement Quantification in Atomic Ensembles

Matteo Fadel, Ayaka Usui, Marcus Huber, Nicolai Friis, and Giuseppe Vitagliano
Phys. Rev. Lett. 127, 010401 – Published 29 June 2021

Abstract

Entanglement measures quantify nonclassical correlations present in a quantum system, but can be extremely difficult to calculate, even more so, when information on its state is limited. Here, we consider broad families of entanglement criteria that are based on variances of arbitrary operators and analytically derive the lower bounds these criteria provide for two relevant entanglement measures: the best separable approximation and the generalized robustness. This yields a practical method for quantifying entanglement in realistic experimental situations, in particular, when only few measurements of simple observables are available. As a concrete application of this method, we quantify bipartite and multipartite entanglement in spin-squeezed Bose-Einstein condensates of 500atoms, by lower bounding the best separable approximation and the generalized robustness only from measurements of first and second moments of the collective spin operator.

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  • Received 30 March 2021
  • Accepted 2 June 2021

DOI:https://doi.org/10.1103/PhysRevLett.127.010401

© 2021 American Physical Society

Physics Subject Headings (PhySH)

General PhysicsQuantum Information, Science & TechnologyAtomic, Molecular & Optical

Authors & Affiliations

Matteo Fadel1,*, Ayaka Usui2, Marcus Huber3,4, Nicolai Friis4,3, and Giuseppe Vitagliano4

  • 1Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
  • 2Quantum Systems Unit, Okinawa Institute of Science and Technology Graduate University, 904-0495 Okinawa, Japan
  • 3Atominstitut, Technische Universität Wien, 1020 Vienna, Austria
  • 4Institute for Quantum Optics and Quantum Information-IQOQI Vienna, Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna, Austria

  • *matteo.fadel@unibas.ch

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Issue

Vol. 127, Iss. 1 — 2 July 2021

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