English

New bound on $S_{1}\times S_{2}$-setting Bell locality of a nonseparable Werner state

Quantum Physics 2026-07-20 v1 Mathematical Physics

Abstract

In many quantum applications it is important to know whether or not a Bell nonlocal two-qudit state exhibits its nonlocality under correlation scenarios with some given numbers S1,S21S_{1},S_{2}\geq1 of generalized quantum measurements at two sites. In the present article, we find analytically a new general condition sufficient for a nonseparable Werner state with a dimension dmin{S1,S2}d\leq\min\{S_{1},S_{2}\} to satisfy all Bell inequalities under every S1×S2S_{1}\times S_{2}-setting correlation scenario with outcomes of an arbitrary spectral type, discrete or continuous - that is, to be S1×S2S_{1}\times S_{2}-setting Bell local, for short. For a variety of S1,S21S_{1},S_{2}\geq1 values, this new general locality condition is beyond Werner's and Barrett's locality conditions for a nonseparable Werner state. We also prove explicitly in the operator terms the optimization result by Terhal et. el. [Phys. Rev. Lett. \textbf{90,} 157903 (2003)] via semi-programming that every nonseparable Werner state with a dimension d>min{S1,S2}d>\min\{S_{1},S_{2}\} is S1×S2S_{1}\times S_{2} -setting Bell local. The new results of the present article are important both for Bell nonlocality theory and for quantum applications based on Bell nonlocality.

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Cite

@article{arxiv.2607.18050,
  title  = {New bound on $S_{1}\times S_{2}$-setting Bell locality of a nonseparable Werner state},
  author = {Elena R. Loubenets},
  journal= {arXiv preprint arXiv:2607.18050},
  year   = {2026}
}

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6 pages