2014/08/26 by Zeng-Bing Chen, Zeng‐Bing Chen, Yao Fu +1
Computer Science · Mathematics · Physics and Astronomy · #Algorithm #Bell test experiments #Bell's theorem #Gaussian #Local hidden variable theory #Mathematics #Optics #Physics #Quadrature (astronomy) #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum entanglement #Quantum mechanics #Quantum nonlocality #State (computer science) #Statistical physics #Wigner distribution function #quant-ph
paper · pdf · doi:10.1103/physreva.90.022124
published as Phys. Rev. A. 90, 022124 (2014)
openalex publication_date 2014/08/26 · arxiv created 2014/09/01 · arxiv updated 2014/09/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
It is a long-standing belief, as pointed out by Bell in 1986, that it is impossible to use a two-mode Gaussian state possessing a positive-definite Wigner function to demonstrate nonlocality as the Wigner function itself provides a local hidden-variable model. In particular, when one performs continuous-variable (CV) quadrature measurements upon a routinely generated CV entanglement, namely, the two-mode squeezed vacuum (TMSV) state, the resulting Wigner function is positive-definite and as such, the TMSV state cannot violate any Bell inequality using CV quadrature measurements. We show here, however, that a Bell inequality for CV states in terms of entropies can be quantum mechanically violated by the TMSV state with two coarse-grained quadrature measurements per site within experimentally accessible parameter regime. The proposed CV entropic Bell inequality is advantageous for an experimental test, especially for a possible loophole-free test of nonlocality, as the quadrature measurements can be implemented with homodyne detections of nearly 100% detection efficiency under current technology.