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Related papers: Activation of Non-Local Quantum Resources

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In this note, we discuss a closed-form necessary and sufficient condition for any two-qubit state to show hidden nonlocality w.r.t the Bell-CHSH inequality. This is then used to numerically compute the relative volume of states showing…

Quantum Physics · Physics 2014-10-29 Rajarshi Pal , Sibasish Ghosh

In this work we investigate the probability of violation of local realism under random measurements in parallel with the strength of these violations as described by resistance to white noise admixture. We address multisetting Bell…

Quantum Physics · Physics 2020-01-22 Anna de Rosier , Jacek Gruca , Fernando Parisio , Tamas Vertesi , Wieslaw Laskowski

The nature of quantum correlations in networks featuring independent sources of entanglement remains poorly understood. Here, focusing on the simplest network of entanglement swapping, we start a systematic characterization of the set of…

Quantum Physics · Physics 2021-04-21 Nicolas Gisin , Quanxin Mei , Armin Tavakoli , Marc-Olivier Renou , Nicolas Brunner

We computationally investigate the complete polytope of Bell inequalities for 2 particles with small numbers of possible measurements and outcomes. Our approach is limited by Pitowsky's connection of this problem to the computationally hard…

Quantum Physics · Physics 2023-03-23 Daniel Collins , Nicolas Gisin

A quantum state can be characterized from the violation of a Bell inequality. The well-known CHSH inequality for example can be used to quantify the fidelity (up to local isometries) of the measured state with respect to the singlet state.…

We prove, modulo a conjecture on quantum steering ellipsoids being true, the existence of the phenomenon of locally inaccessible hidden quantum correlations. That is, the existence of two-particle states whose hidden quantum correlations…

Quantum Physics · Physics 2024-12-23 Andrés F. Ducuara , Cristian E. Susa , Paul Skrzypczyk

Bell inequalities are an important tool in device-independent quantum information processing because their violation can serve as a certificate of relevant quantum properties. Probably the best known example of a Bell inequality is due to…

Given the goal of maximizing CHSH violation, we compare the optimal strategies of entanglement and nonlocality distillation. In the limit of the number of copies of the shared state, entanglement distillation is guaranteed to work by…

Quantum Physics · Physics 2026-03-03 Peter Høyer , Jibran Rashid , Razeen ud Din

A correlation inequality is derived from local realism and a supplementary assumption. Unlike Clauser-Horne (CH) inequality [or Clauser-Horne-Shimony-Holt (CHSH) inequality] which is violated by quantum mechanics by a factor of $\sqrt 2$,…

Quantum Physics · Physics 2007-05-23 M. Ardehali

We show that a maximal violation of the Bell-CHSH inequality for two entangled qubits, i.e., Bell non-locality, is a direct consequence of a local bit erasure by means of a quasi-stochastic process, i.e., a stochastic process in which some…

Quantum Physics · Physics 2024-05-28 Kelvin Onggadinata , Pawel Kurzynski , Dagomir Kaszlikowski

Measurement incompatibility and quantum non-locality are two key features of quantum theory. Violations of Bell inequalities require quantum entanglement and incompatibility of the measurements used by the two parties involved in the…

Mathematical Physics · Physics 2023-03-30 Faedi Loulidi , Ion Nechita

Nonlocality is a fascinating and counterintuitive aspect of Nature, revealed by the violation of a Bell inequality. The standard and easiest configuration in which Bell inequalities can be measured has been proposed by…

Quantum Physics · Physics 2015-03-17 Enrico Pomarico , Jean-Daniel Bancal , Bruno Sanguinetti , Anas Rochdi , Nicolas Gisin

We investigate quantum correlations appearing for two qubit detectors which are initially uncorrelated and locally coupled to a massless scalar field in a vacuum state. Under the perturbation up to the second order in the coupling, the…

Quantum Physics · Physics 2020-11-09 Akira Matsumura , Yasusada Nambu

We discuss the relations between the violation of the CHSH Bell inequality for systems of two qubits on the one side and entanglement of formation, local filtering operations, and the entropy and purity on the other. We calculate the…

Quantum Physics · Physics 2009-11-07 Frank Verstraete , Michael M. Wolf

Sufficient conditions for (the non-violation of) the Bell-CHSH inequalities in a mixed state of a two-qubit system are: 1) The linear entropy of the state is not smaller than 0.5, 2) The sum of the conditional linear entropies is…

Quantum Physics · Physics 2009-11-10 Emilio Santos

We discuss a family of W-class states describing three-qubit systems. For such systems, we analyze the relations between the entanglement measures and the nonlocality parameter for a two-mode mixed state related to the two-qubit subsystem.…

Quantum Physics · Physics 2025-01-08 Joanna K. Kalaga , Wiesław Leoński , Jan Peřina

The relation between Bell-CHSH violation and factorization of Hilbert space is considered here. That is, a state which is local in the sense of the Bell-CHSH inequality under a certain factorization of the underlying Hilbert space can be…

We investigate the nonlocality distributions among multiqubit systems based on the maximal violations of the Clauser-Horne-Shimony-Holt (CHSH) inequality of reduced pairwise qubit systems. We present a trade-off relation satisfied by these…

Quantum Physics · Physics 2015-12-31 Hui-Hui Qin , Shao-Ming Fei , Xianqing Li-Jost

We derive a new inequality that is necessary and sufficient to show EPR-steering in a scenario employing only correlations between two arbitrary dichotomic measurements on each party. Thus the inequality is a complete steering analogy of…

Quantum Physics · Physics 2017-12-19 Parth Girdhar , Eric G. Cavalcanti

As a way of saving quantum resources, recycling of Bell nonlocality has been experimentally studied, but restricted to sequential unsharp measurements. However, it has been theoretically shown recently that projective measurements are…

Quantum Physics · Physics 2022-12-08 Ya Xiao , Yan-Xin Rong , Xin-Hong Han , Shuo Wang , Xuan Fan , Wei-Chen Li , Yong-Jian Gu