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Related papers: CHSH violation and entropy - concurrence plane

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We present a set of Bell inequalities for multiqubit quantum systems. These Bell inequalities are shown to be able to detect multiqubit entanglement better than previous Bell inequalities such as Werner-Wolf-Zukowski- Brukner ones.…

Quantum Physics · Physics 2012-12-11 Ming Li , Shao-Ming Fei

We analyze qubit-qubit entanglement from an energetic perspective and reveal an energetic trade-off between quantum coherence and entanglement. We decompose each qubit internal energy into a coherent and an incoherent component. The qubits'…

Quantum Physics · Physics 2026-04-08 Kiarn T. Laverick , Samyak P. Prasad , Pascale Senellart , Maria Maffei , Alexia Auffèves

Exploring an analytical expression for the convex roof of the pure state squared concurrence for rank 2 mixed states the entanglement of a system of three particles under decoherence is studied, using the monogamy inequality for mixed…

Quantum Physics · Physics 2009-08-28 Thiago R. de Oliveira

The entanglement content of superpositions of quantum states is investigated based on a measure called {\it concurrence}. Given a bipartite pure state in arbitrary dimension written as the quantum superposition of two other such states, we…

Quantum Physics · Physics 2009-11-13 J. Niset , N. J. Cerf

We study the explicit relation between violation of Bell inequalities and bipartite distillability of multi-qubit states. It has been shown that even though for $N\ge 8$ there exist $N$-qubit bound entangled states which violates a Bell…

Quantum Physics · Physics 2009-11-13 Soojoon Lee , Jinhyoung Lee , Jaewan Kim

Based on the violation of Bell inequalities, we can verify quantum random numbers by examining the correlation between device inputs and outputs. In this paper, we derive the maximum quantum value of the parity-CHSH inequality for a…

Quantum Physics · Physics 2025-04-21 Guannan Zhang , Jiamin Xu , Ming Li , Shuqian Shen , Lei Li , Shao-ming Fei

Despite the successful experimental generation and verification of genuine multipartite entanglement, several existing entanglement measures remain insufficient to reliably capture its presence. In this study, we overcome this challenge by…

Quantum Physics · Physics 2025-10-20 Shruti Aggarwal

We propose a new method for detecting entanglement of two qubits and discuss its relation with the Clauser-Horne-Shimony-Holt (CHSH) Bell inequality. Without the need for full quantum tomography for the density matrix we can experimentally…

Quantum Physics · Physics 2007-05-23 Kai Chen , Ling-An Wu

Connecting incompatibility in measurements with the violation of local realism is one of the fundamental avenues of research. For two qubits, any incompatible pair of projective measurements can violate Clauser-Horne-Shimony-Holt (CHSH)…

Quantum Physics · Physics 2024-11-19 Sudipta Mondal , Pritam Halder , Saptarshi Roy , Aditi Sen De

We provide a general description of the phenomenon of entanglement in bipartite systems, as it manifests in micro and macro physical systems, as well as in human cognitive processes. We do so by observing that when genuine coincidence…

We derive a lower bound for the concurrence of mixed bipartite quantum states, valid in arbitrary dimensions. As a corollary, a weaker, purely algebraic estimate is found, which detects mixed entangled states with positive partial…

Quantum Physics · Physics 2009-11-10 Florian Mintert , Marek Kus , Andreas Buchleitner

We derive an experimentally observable lower bound on concurrence of mixed quantum states in terms of an entanglement witness, relating measurements on single states with those on two copies.

Quantum Physics · Physics 2009-11-13 Florian Mintert

We study the entanglement of a multipartite quantum state. An inequality between the bipartite concurrence and the multipartite concurrence is obtained. More effective lower and upper bounds of the multipartite concurrence are obtained. By…

Quantum Physics · Physics 2015-05-19 Ming Li , Shao-Ming Fei , Zhi-Xi Wang

We consider properties of states of many qubits, which arise after sending certain entangled states via various noisy channels (white noise, coloured noise, local depolarization, dephasing and amplitude damping). Entanglement of these…

Quantum Physics · Physics 2015-05-13 Wieslaw Laskowski , Tomasz Paterek , Caslav Brukner , Marek Zukowski

The only information available about an alleged source of entangled quantum states is the amount $S$ by which the Clauser-Horne-Shimony-Holt (CHSH) inequality is violated: nothing is known about the nature of the system or the measurements…

Quantum Physics · Physics 2009-12-19 C. -E. Bardyn , T. C. H. Liew , S. Massar , M. McKague , V. Scarani

A classification of multipartite entanglement in qubit systems is introduced for pure and mixed states. The classification is based on the robustness of the said entanglement against partial trace operation. Then we use current machine…

Quantum Physics · Physics 2022-10-17 F. El Ayachi , M. El Baz

Cluster states are a new type of multiqubit entangled states with entanglement properties exceptionally well suited for quantum computation. In the present work, we experimentally demonstrate that correlations in a four-qubit linear cluster…

Quantum Physics · Physics 2009-11-11 Philip Walther , Markus Aspelmeyer , Kevin J. Resch , Anton Zeilinger

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

Recently, a basis-invariant measure of coherence known as the intrinsic degree of coherence has been established for classical and single-particle quantum states [JOSA B {\bf 36}, 2765 (2019)]. Using the same mathematical construction, in…

Quantum Physics · Physics 2020-03-30 Nilakantha Meher , Abu Saleh Musa Patoary , Girish Kulkarni , Anand K. Jha

We provide an analytical tripartite-study from the generalized $R$-matrix. It provides the upper bound of the maximum violation of Mermin's inequality. For a generic 2-qubit pure state, the concurrence or $R$-matrix characterizes the…

Quantum Physics · Physics 2023-01-11 Xingyu Guo , Chen-Te Ma