English
Related papers

Related papers: Optimal measurements for nonlocal correlations

200 papers

We show that arbitrary functions of continuous variables, e.g. position and momentum, can be used to generate tests that distinguish quantum theory from local hidden variable theories. By optimising these functions, we obtain more robust…

Quantum Physics · Physics 2009-11-16 Q. Y. He , E. G. Cavalcanti , M. D. Reid , P. D. Drummond

Tests of local realism and their applications aim for very high confidence in their results even in the presence of potentially adversarial effects. For this purpose, one can measure a quantity that reflects the amount of violation of local…

Quantum Physics · Physics 2013-11-26 Yanbao Zhang , Scott Glancy , Emanuel Knill

We will show for undergraduate and graduate students of physics that Quantum Mechanics is an incomplete and non-local theory. The problem of non-locality is discussed by analyzing the Bell's theorem where are considered correlations between…

General Physics · Physics 2011-03-03 M. Cattani

No-signaling theories, which can contain nonlocal correlations stronger than classical correlations but limited by the no-signaling condition, have deepened our understanding of the quantum theory. In principle, the nonlocality of these…

Quantum Physics · Physics 2016-11-01 Zhu Cao , Tianyi Peng

The exploration of the concept of nonlocality beyond standard Bell scenarios in quantum network architectures unveils fundamentally new forms of correlations that hold a strong potential for future applications of quantum communication…

Device independent protocols based on Bell nonlocality, such as quantum key distribution and randomness generation, must ensure no adversary can have prior knowledge of the measurement outcomes. This requires a measurement independence…

Quantum Physics · Physics 2020-12-08 Michael J. W. Hall , Cyril Branciard

On the basis of local realism theory, nonlocal information is necessary for violation of Bell's inequality. From a theoretical point of view, nonlocal information is essentially the mutual information on distant outcome and measurement…

Quantum Physics · Physics 2011-02-02 Yang Xiang , Shi-Jie Xiong

We address the issue of reducing the resource required to compute information-theoretic quantum correlation measures like quantum discord and quantum work deficit in two qubits and higher dimensional systems. We show that determination of…

Quantum Physics · Physics 2015-12-18 Titas Chanda , Tamoghna Das , Debasis Sadhukhan , Amit Kumar Pal , Aditi Sen De , Ujjwal Sen

We examine the problem of exhibiting Bell nonlocality for a two-qudit entangled pure state using a randomly chosen set of mutually unbiased bases (MUBs). Interestingly, even if we employ only two-setting Bell inequalities, we find a…

Quantum Physics · Physics 2022-07-19 Gelo Noel M. Tabia , Varun Satya Raj Bavana , Shih-Xian Yang , Yeong-Cherng Liang

In this work, we deal with the relaxation of two central assumptions in standard locally realistic hidden variable (LRHV) inequalities: free will in choosing measurement settings, and the presence of perfect detectors at the measurement…

Quantum Physics · Physics 2023-02-07 Abhishek Sadhu , Siddhartha Das

Two of the most intriguing features of quantum physics are the uncertainty principle and the occurrence of nonlocal correlations. The uncertainty principle states that there exist pairs of incompatible measurements on quantum systems such…

Quantum Physics · Physics 2013-01-21 Marco Tomamichel , Esther Hänggi

Informationally complete measurements allow the estimation of expectation values of any operator on a quantum system, by changing only the data-processing of the measurement outcomes. In particular, an informationally complete measurement…

Quantum Physics · Physics 2007-05-23 G. M. D'Ariano , P. Perinotti , M. F. Sacchi

We show that quantum computers can be used for producing large $n$-partite nonlocality, thereby providing a method to benchmark them. The main challenges to overcome are as follows: (i) The interaction topology might not allow arbitrary…

Quantum Physics · Physics 2025-01-13 Jan Lennart Bönsel , Otfried Gühne , Adán Cabello

Bell non-locality represents the ultimate consequence of quantum entanglement, fundamentally undermining the classical tenet that spatially-separated degrees of freedom possess objective attributes independently of the act of their…

Quantum Physics · Physics 2021-04-13 Irénée Frérot , Tommaso Roscilde

The problem of computing the local hidden variable (LHV) value of a Bell inequality plays a central role in the study of quantum nonlocality. In particular, this problem is the first step towards characterizing the LHV polytope of a given…

Quantum Physics · Physics 2023-02-08 Dardo Goyeneche , Wojciech Bruzda , Ondřej Turek , Daniel Alsina , Karol Życzkowski

We show, for any finite $n \geq 2$, that there exist quantum correlations obtained from performing $n$ dichotomic quantum measurements in a bipartite Bell scenario, which cannot be reproduced by mixtures of measurement devices with at most…

Quantum Physics · Physics 2025-07-16 Lucas Tendick

Non-local correlations are usually understood through the outcomes of alternative measurements (on two or more parts of a system) that cannot altogether actually be carried out in an experiment. Indeed, a joint input/output -- e.g.,…

Quantum Physics · Physics 2015-11-11 Stefan Wolf

Measurement incompatibility describes two or more quantum measurements whose expected joint outcome on a given system cannot be defined. This purely non-classical phenomenon provides a necessary ingredient in many quantum information tasks…

Quantum Physics · Physics 2020-04-01 Francesco Buscemi , Eric Chitambar , Wenbin Zhou

Bell nonlocality, the fact that local hidden variable models cannot reproduce the correlations obtained by measurements on entangled states, is a cornerstone in our modern understanding of quantum theory. Apart from its fundamental…

Quantum Physics · Physics 2020-09-04 M. G. M. Moreno , Samuraí Brito , Ranieri V. Nery , Rafael Chaves

Quantum computational experiments exploiting Noisy Intermediate-Scale Quantum (NISQ) devices to demonstrate violation of a Bell inequality are proposed. They consist of running specified quantum algorithms on few-qubit computers. If such a…

Quantum Physics · Physics 2020-09-02 H. W. L. Naus , H. Polinder