Characterizing quantum correlations in the nonsignaling framework

Abstract

Quantum correlations forms a subset of the set of nonsignaling boxes. This allows us to characterize quantum correlations as a convex combination of the extremal boxes of the nonsignaling polytope which are Popescu-Rohrlich boxes (maximally nonlocal boxes) and local deterministic boxes. There exists multiple decomposition of quantum correlations in the context of the nonsignaling polytope. I find that the existence of Popescu-Rohrlich box decomposition for local boxes associates two notions of discord which capture nonclassicality of quantum correlations originating from Bell nonlocality and EPR-steering. I introduce, Bell and Mermin discord, and demonstrate that any bipartite nonsignaling box admits a three-way decomposition. This decomposition allows us to isolate the origin of nonclassicality into three disjoint sources: a Popescu-Rohrlich box, a maximally local box that detects EPR-steering, and a classical correlation. Interestingly, I show that all non-null quantum discord states which are neither classical-quantum states nor quantum-classical states can give rise to nonclassical correlations which have non-null Bell and/or Mermin discord for suitable noncommuting measurements. I introduce two notions of genuine discord, which are the generalizations of Bell and Mermin discord to the multipartite boxes, to characterize the presence of genuine nonclassicality in multipartite quantum correlations.

PhD thesis submitted and defended successfully at the Indian Institute of Science Education and Research Mohali. This thesis is based on articles arXiv:1407.3170v4, arXiv:1407.5588v5 and arXiv:1410.1472v3. 151 pages and 9 figures

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Cited by in corpus (4)

• Nonclassicality of local bipartite correlations
• Superunsteerability as a quantifiable resource for random access codes assisted by Bell-diagonal states
• Operational nonclassicality of local multipartite correlations in the limited-dimensional simulation scenario
• Certifying quantumness beyond steering and nonlocality and its implications on quantum information processing