A Witness of GHZ Entanglement Using Only Collective Spin Measurements

Fuente: arXiv
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Main Authors: Zaw, Lin Htoo, Huynh-Vu, Khoi-Nguyen, Scarani, Valerio
Format: Preprint
Published: 2023
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author Zaw, Lin Htoo
Huynh-Vu, Khoi-Nguyen
Scarani, Valerio
author_facet Zaw, Lin Htoo
Huynh-Vu, Khoi-Nguyen
Scarani, Valerio
contents Of existing entanglement witnesses that utilize only collective measurements of a spin ensemble, not all can detect genuine multipartite entanglement (GME), and none can detect Greenberger-Horne-Zeilinger (GHZ) states beyond the tripartite case. We fill this gap by introducing an entanglement witness that detects GME of spin ensembles, whose total spin is half-integer, using only collective spin measurements. Our witness is based on a nonclassicality test introduced by Tsirelson, and solely requires the measurement of total angular momentum along different directions. States detected by our witness are close to a family of GHZ-like states, which includes GHZ states of an odd number of spin-half particles. We also study the robustness of our witness under depolarizing noise, and derive exact noise bounds for detecting noisy GHZ states.
format Preprint
id arxiv_https___arxiv_org_abs_2311_00805
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A Witness of GHZ Entanglement Using Only Collective Spin Measurements
Zaw, Lin Htoo
Huynh-Vu, Khoi-Nguyen
Scarani, Valerio
Quantum Physics
Of existing entanglement witnesses that utilize only collective measurements of a spin ensemble, not all can detect genuine multipartite entanglement (GME), and none can detect Greenberger-Horne-Zeilinger (GHZ) states beyond the tripartite case. We fill this gap by introducing an entanglement witness that detects GME of spin ensembles, whose total spin is half-integer, using only collective spin measurements. Our witness is based on a nonclassicality test introduced by Tsirelson, and solely requires the measurement of total angular momentum along different directions. States detected by our witness are close to a family of GHZ-like states, which includes GHZ states of an odd number of spin-half particles. We also study the robustness of our witness under depolarizing noise, and derive exact noise bounds for detecting noisy GHZ states.
title A Witness of GHZ Entanglement Using Only Collective Spin Measurements
topic Quantum Physics
url https://arxiv.org/abs/2311.00805