Violation of bell-chsh inequalities through optimal local filters in the vacuum

Akira Matsumura, Yasusada Nambu

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


We investigate quantum correlations appearing for two-qubit detectors which are initially uncorrelated and locally coupled to a massless scalar field in a vacuum state. Under the perturbation up to the second order in the coupling, the state of the detectors can be entangled through the interaction with the scalar field but satisfies the Bell-CHSH inequality. The violation of the Bell-CHSH inequality for such an entangled state is revealed by local filtering operations. In this paper, we construct the optimal filtering operations for the qubit detectors and derive the success probability of the filtering. The success probability characterizes the reliability of revealing the violation of the Bell-CHSH inequality by the filtering operations. Through these analyses, we demonstrate a trade-off relation between the success probability and the size of parameter region showing the violation of the Bell-CHSH inequality.

Original languageEnglish
Pages (from-to)542-559
Number of pages18
JournalQuantum Reports
Issue number4
Publication statusPublished - Dec 2020

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Atomic and Molecular Physics, and Optics
  • Statistical and Nonlinear Physics
  • Physics and Astronomy (miscellaneous)


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