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Information processing in generalized probabilistic theories
- J. Barrett
- 28 August 2005
A framework in which a variety of probabilistic theories can be defined, including classical and quantum theories, and many others, is introduced, and a tensor product rule for combining separate systems can be derived.
On the reality of the quantum state
A no-go theorem on the reality of the quantum state is demonstrated. If the quantum state merely represents information about the physical state of a system, then predictions that contradict those of…
Nonlocal correlations as an information-theoretic resource
It is well known that measurements performed on spatially separated entangled quantum systems can give rise to correlations that are nonlocal, in the sense that a Bell inequality is violated. They…
No signaling and quantum key distribution.
A key distribution scheme provably secure against general attacks by a postquantum eavesdropper limited only by the impossibility of superluminal signaling is described, which stems from violation of a Bell inequality.
Many worlds? : Everett, quantum theory, and reality
Many Worlds: an Introduction 1. WHY MANY WORLDS? 1. Decoherence and Ontology 2. Quasiclassical Realms 3. Macroscopic Superpositions, Decoherent Histories, and the Emergence of Hydrodynamical…
Nonsequential positive-operator-valued measurements on entangled mixed states do not always violate a Bell inequality
- J. Barrett
- 7 July 2001
We present a local-hidden-variable model for positive-operator-valued measurements (an LHVPOV model) ) on a class of entangled generalized Werner states, thus demonstrating that such measurements do…
Quantum common causes and quantum causal models
- John-Mark Allen, J. Barrett, Dominic C. Horsman, Ciarán M. Lee, R. Spekkens
- 29 September 2016
Reichenbach’s principle asserts that if two observed variables are found to be correlated, then there should be a causal explanation of these correlations. Furthermore, if the explanation is in terms…
Definitions of multipartite nonlocality
n a multipartite setting, it is possible to distinguish quantum states that are genuinely n-way entangled from those that are separable with respect to some bipartition. Similarly, the nonlocal…
No ψ-epistemic model can fully explain the indistinguishability of quantum states.
This work considers models that are defined for a single quantum system of dimension d, such that the independence condition does not arise, and derives an upper bound on the extent to which the probability distributions can overlap.
Generalized no-broadcasting theorem.
We prove a generalized version of the no-broadcasting theorem, applicable to essentially any nonclassical finite-dimensional probabilistic model satisfying a no-signaling criterion, including ones…