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We show that standard nonlocal boxes, also known as Popescu-Rohrlich machines, are not sufficient to simulate any nonlocal correlations that do not allow signalling. This was known in the multipartite scenario, but we extend the result to…

A set of nonlocal correlations that have come to be known as a PR box suggest themselves as a natural unit of nonlocality, much as a singlet is a natural unit of entanglement. We present two results relevant to this idea. One is that a wide…

Quantum Physics · Physics 2007-10-22 Jonathan Barrett , Stefano Pironio

It is shown that Popescu-Rohrlich nonlocal boxes (beating the Tsirelson bound for Bell inequality) do exist in the existing structures of both quantum and classical theory. In particular, we design an explicit example of measure-and-prepare…

Quantum Physics · Physics 2020-10-27 Martin Plávala , Mário Ziman

Imagine a task in which a group of separated players aim to simulate a statistic that violates a Bell inequality. Given measurement choices the players shall announce an output based solely on the results of local operations -- which they…

Quantum Physics · Physics 2011-11-04 Manuel Forster , Stefan Wolf

We prove that there is no finite-alphabet nonlocal box that generates exactly those correlations that can be generated using a maximally entangled pair of qubits. More generally, we prove that if some finite-alphabet nonlocal box is strong…

Quantum Physics · Physics 2017-08-09 Cole A. Graham , William M. Hoza

We investigate network nonlocality in the triangle scenario when all three parties have no input and binary outputs. Through an explicit example, we prove that this minimal scenario supports nonlocal correlations compatible with…

Nonlocal boxes are conceptual tools that capture the essence of the phenomenon of quantum non-locality, central to modern quantum theory and quantum technologies. We introduce network nonlocal boxes tailored for quantum networks under the…

Quantum Physics · Physics 2023-11-17 Jean-Daniel Bancal , Nicolas Gisin

Supraquantum nonlocality refers to correlations that are more nonlocal than allowed by quantum theory but still physically conceivable in post-quantum theories, in the sense of respecting the basic no-faster-than-light communication…

Quantum Physics · Physics 2018-02-02 Andreas Ketterer , Adrien Laversanne-Finot , Leandro Aolita

Nonlocality swapping of bipartite binary correlated boxes can be realized by a \emph{coupler} ($\chi$) in nonsignaling models. By studying the swapping process we find that the previous bipartite coupler can be applied to the swapping of…

Quantum Physics · Physics 2011-10-04 Chao Li , Ming Yang , Qing Yang , Zhuo-Liang Cao

A classical non-signalling (or causal) box is an operation on classical bipartite input with classical bipartite output such that no signal can be sent from a party to the other through the use of the box. The quantum counterpart of such…

Quantum Physics · Physics 2009-11-11 M. Piani , M. Horodecki , P. Horodecki , R. Horodecki

In instantaneous nonlocal quantum computation, two parties cooperate in order to perform a quantum computation on their joint inputs, while being restricted to a single round of simultaneous communication. Previous results showed that…

Quantum Physics · Physics 2016-08-24 Anne Broadbent

We propose a class of nonlocal boxes named functional boxes which include a generalization of the Popescu-Rohrlich(PR) box as a special case. We show that every functional box corresponding to an additively inseparable function can make…

Quantum Physics · Physics 2011-09-30 Guoming Wang

A non-local box is a virtual device that has the following property: given that Alice inputs a bit at her end of the device and that Bob does likewise, it produces two bits, one at Alice's end and one at Bob's end, such that the XOR of the…

Quantum Physics · Physics 2012-02-22 A. Broadbent , A. A. Methot

One of the most intriguing features of quantum physics is the non-locality of correlations that can be obtained by measuring entangled particles. Recently, it has been noticed that non-locality can be studied without reference to the…

Quantum Physics · Physics 2009-11-13 Valerio Scarani

It is known that there exist non-local correlations that respect no-signaling criterion, but violate Bell-type inequalities more than quantum-mechanical correlations. Such super quantum correlations were introduced as the Popescu-Rohrlich…

Quantum Physics · Physics 2014-12-15 Indranil Chakrabarty , Tanumoy Pramanik , Arun K Pati , Pankaj Agrawal

Pure states are very important in any theory since they represent states of maximal information about the system within the theory. Here, we show that no non-trivial (not local realistic) extremal states (boxes) of general no-signaling…

Quantum Physics · Physics 2016-08-03 Ravishankar Ramanathan , Jan Tuziemski , Michał Horodecki , Paweł Horodecki

A well known cryptographic primitive is so called random access code. Namely, Alice is to send to Bob one of two bits, so that Bob has the choice which bit he wants to learn about. However at any time Alice should not learn Bob's choice,…

Quantum Physics · Physics 2016-10-05 Andrzej Grudka , Michał Horodecki , Ryszard Horodecki , Antoni Wójcik

Here we introduce the concept of classical input - quantum output (C-Q) non-signalling boxes, a generalisation of the classical input - classical output (C-C) non-signalling boxes. We argue that studying such objects leads to a better…

Quantum Physics · Physics 2024-08-28 Carolina Moreira Ferrera , Robin Simmons , James Purcell , Daniel Collins , Sandu Popescu

We show that there is a stronger form of bipartite quantum nonlocality in which systems that never interacted are as nonlocal as allowed by no-signaling. For this purpose, we first show that nonlocal boxes, theoretical objects that violate…

Quantum Physics · Physics 2012-11-26 Adan Cabello

It is demonstrated that identifying information-theoretic limitations of quantum Bell nonlocality alone cannot completely distinguish quantum theory from generalized nonsignaling theories. To this end, an information-theoretic concept of…

Quantum Physics · Physics 2025-12-15 Chellasamy Jebarathinam
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