From Einstein-Podolsky-Rosen paradox to quantum nonlocality: experimental investigation of quantum correlations

2016 ◽  
Author(s):  
Jin-Shi Xu ◽  
Chuan-Feng Li ◽  
Guang-Can Guo
2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Elisa Bäumer ◽  
Nicolas Gisin ◽  
Armin Tavakoli

AbstractIncreasingly sophisticated quantum computers motivate the exploration of their abilities in certifying genuine quantum phenomena. Here, we demonstrate the power of state-of-the-art IBM quantum computers in correlation experiments inspired by quantum networks. Our experiments feature up to 12 qubits and require the implementation of paradigmatic Bell-State Measurements for scalable entanglement-swapping. First, we demonstrate quantum correlations that defy classical models in up to nine-qubit systems while only assuming that the quantum computer operates on qubits. Harvesting these quantum advantages, we are able to certify 82 basis elements as entangled in a 512-outcome measurement. Then, we relax the qubit assumption and consider quantum nonlocality in a scenario with multiple independent entangled states arranged in a star configuration. We report quantum violations of source-independent Bell inequalities for up to ten qubits. Our results demonstrate the ability of quantum computers to outperform classical limitations and certify scalable entangled measurements.


2021 ◽  
pp. 2150074
Author(s):  
Youssef Khedif ◽  
Mohammed Daoud

We investigate the quantum correlations of a two-qubit XYZ Heisenberg spin-1/2 chain model with Dzyaloshinskii–Moriya interaction. The two-qubit system is considered in thermal equilibrium. The variations of logarithmic negativity, uncertainty-induced quantum nonlocality (UIN) and trace distance discord, versus the parameters characterizing the system, are analyzed. The results show that the UIN measure captures quantum correlations that cannot be revealed by entanglement and trace discord. We also show that the Dzyaloshinskii–Moriya interaction enhances the non-classical correlations between the spins and can weaken the undesirable destructive effects of thermal fluctuations. In addition, an entangled–unentangled phase transition can be detected from the behavior of logarithmic negativity.


2010 ◽  
Vol 8 (2) ◽  
Author(s):  
Narayanan Kutty Karuppath ◽  
Achuthan Panajikunnath

Photoniques ◽  
2021 ◽  
pp. 55-58
Author(s):  
Claude Fabre

In 1935, Schrödinger introduced the word "entanglement" to describe a situation examined in the famous Einstein-Podolsky-Rosen paper published a few months before. The proper nature of quantum correlations that exist when a two-partite system is in an entangled state was a subject of controversy. In contrast to many other subjects, the debate about the nature of entanglement came quite recently to an end.


2019 ◽  
Vol 5 (4) ◽  
pp. eaav8370 ◽  
Author(s):  
Avishy Carmi ◽  
Eliahu Cohen

If nature allowed nonlocal correlations other than those predicted by quantum mechanics, would that contradict some physical principle? Various approaches have been put forward in the past two decades in an attempt to single out quantum nonlocality. However, none of them can explain the set of quantum correlations arising in the simplest scenarios. Here, it is shown that generalized uncertainty relations, as well as a specific notion of locality, give rise to both familiar and new characterizations of quantum correlations. In particular, we identify a condition, relativistic independence, which states that uncertainty relations are local in the sense that they cannot be influenced by other experimenters’ choices of measuring instruments. We prove that theories with nonlocal correlations stronger than the quantum ones do not satisfy this notion of locality, and therefore, they either violate the underlying generalized uncertainty relations or allow experimenters to nonlocally tamper with the uncertainty relations of their peers.


2007 ◽  
Vol 15 (26) ◽  
pp. 18236 ◽  
Author(s):  
K. N. Cassemiro ◽  
A. S. Villar ◽  
M. Martinelli ◽  
P. Nussenzveig

2010 ◽  
Vol 1 (1) ◽  
Author(s):  
Jin-Shi Xu ◽  
Xiao-Ye Xu ◽  
Chuan-Feng Li ◽  
Cheng-Jie Zhang ◽  
Xu-Bo Zou ◽  
...  

Open Physics ◽  
2017 ◽  
Vol 15 (1) ◽  
pp. 586-597 ◽  
Author(s):  
Donald A. Graft

AbstractThis paper argues that quantum nonlocality (QNL) has not been rigorously proven, despite the existence of recent Einstein-Podolsky-Rosen-Bohm (EPRB) experiments that are claimed to be ‘loophole-free’. First, readers are alerted to rhetorical arguments, which are unfortunately often appealed to in the QNL debate, to empower readers to identify and reject such arguments. Second, logical problems in QNL proofs are described and exemplified by a discussion of the projection postulate problem. Third, experimental issues are described and exemplified by a discussion of the postselection problem. The paper concludes that QNL has not been proven and that locality cannot be excluded.


2014 ◽  
Vol 89 (1) ◽  
Author(s):  
Priyanka Chowdhury ◽  
Tanumoy Pramanik ◽  
A. S. Majumdar ◽  
G. S. Agarwal

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