Seminários

Seminários do grupo de Óptica e Informação Quântica

Mafalda Almeida (CQT, Natinal University of Singapore)

Sexta-feira 19/8/2011, 11h00, sala A5-01.

Título: Information-Causality Is Not Good Enough

Resumo: Quantum systems can share correlations which are stronger than those
allowed by any classical (or local) theory. It is however unknown what
limits the strength of quantum correlations. Information-causality
(IC) has recently been proposed as the physical principle that would
define quantum nonlocality. Indeed, this principle is always satisfied
by quantum physics and succeed in ruling out many supra-quantum
correlations (at least when only two systems are considered).

In this talk I will present a recent work where we investigate the
behavior of IC in the multipartite scenario. We consider the simplest
framework, where three distant parties establish correlations by
measuring, each, two observables with two possible outcomes. We show
that all, but one, nonlocal extremal correlations in this scenario
violate information causality. This undetected correlation is shown to
satisfy any bipartite physical principle.

Joint work with T. H. Yang, D. Cavalcanti, C. Teo and V. Scarani from
CQT, Singapore. (available in arXiv:1108.2293)