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Related papers: The Dynamics of the Bounds of Squared Concurrence

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We derive an analytical expression for the lower bound of the concurrence of mixed quantum states of composite 2xK systems. In contrast to other, implicitly defined entanglement measures, the numerical evaluation of our bound is…

Quantum Physics · Physics 2009-11-10 Artur Lozinski , Andreas Buchleitner , Karol Zyczkowski , Thomas Wellens

We study the concurrence of arbitrary multipartite mixed quantum states. An explicit lower bound of the concurrence is derived, which detects quantum entanglement of some states better than some separability criteria, and gives sufficient…

Quantum Physics · Physics 2009-11-13 Ming Li , Shao-Ming Fei , Zhi-XiWang

We provide a class of lower bounds for concurrence based on symmetric measurements. We show that our lower bounds estimate the quantum entanglement better than some existing lower bounds by detailed examples. Moreover, our lower bounds can…

Quantum Physics · Physics 2025-03-28 Hao-Fan Wang , Shao-Ming Fei

The quantum entanglements are studied in terms of the invariants under local unitary transformations. A generalized formula of concurrence for $N$-dimensional quantum systems is presented. This generalized concurrence has potential…

Quantum Physics · Physics 2009-11-07 Sergio Albeverio , Shao-Ming Fei

For bipartite quantum states we obtain lower bounds on two important entanglement measures, concurrence and negativity, studying the inequalities for the expectation value of a projector on some subspace of the Hilbert space. Several…

Quantum Physics · Physics 2020-08-05 K. V. Antipin

The bounds on concurrence of the superposition state in terms of those of the states being superposed are studied in this paper. The bounds on concurrence are quite different from those on the entanglement measure based on von Neumann…

Quantum Physics · Physics 2009-11-13 Chang-shui Yu , X. X. Yi , He-shan Song

We study the concurrence of four-qubit quantum states and provide analytical lower bounds of concurrence in terms of the monogamy inequality of concurrence for qubit systems. It is shown that these lower bounds are able to improve the…

Quantum Physics · Physics 2014-02-11 Xue-Na Zhu , Shao-Ming Fei

We present a lower bound of concurrence for arbitrary dimensional bipartite quantum states. This lower bound may be used to improve all the known lower bounds of concurrence. Moreover, the lower bound gives rise to an operational sufficient…

Quantum Physics · Physics 2011-12-26 Ming-Jing Zhao , Xue-Na Zhu , Shao-Ming Fei , Xianqing Li-Jost

We introduce an intuitive measure of genuine multipartite entanglement which is based on the well-known concurrence. We show how lower bounds on this measure can be derived that also meet important characteristics of an entanglement…

Quantum Physics · Physics 2011-06-21 Zhi-Hao Ma , Zhi-Hua Chen , Jing-Ling Chen , Christoph Spengler , Andreas Gabriel , Marcus Huber

Concurrence is an important entanglement measure for states in finite-dimensional quantum systems that was explored intensively in the last decade. In this paper, we extend the concept of concurrence to infinite-dimensional bipartite…

Quantum Physics · Physics 2012-03-20 Yu Guo , Jinchuan Hou , Yuncai Wang

Monogamy of entanglement is generally discussed using a bipartite entanglement measure as an upper bound. Here we discuss a new kind of monogamous relation where the upper bound is given by a multipartite measure of entanglement, the…

Quantum Physics · Physics 2013-03-27 Marcio F. Cornelio

We obtain analytical lower bounds on the concurrence of bipartite quantum systems in arbitrary dimensions related to the violation of separability conditions based on local uncertainty relations and on the Bloch representation of density…

Quantum Physics · Physics 2009-11-13 Julio I. de Vicente

Entanglement monotones, such as the concurrence, are useful tools to characterize quantum correlations in various physical systems. The computation of the concurrence involves, however, difficult optimizations and only for the simplest case…

Quantum Physics · Physics 2012-11-20 Zhi-Hua Chen , Zhi-Hao Ma , Otfried Gühne , Simone Severini

We derive an explicit analytic estimate for the entanglement of a large class of bipartite quantum states which extends into bound entanglement regions. This is done by using an efficiently computable concurrence lower bound, which is…

We present observable lower bounds for several bipartite entanglement measures including entanglement of formation, geometric measure of entanglement, concurrence, convex-roof extended negativity, and G-concurrence. The lower bounds…

Quantum Physics · Physics 2016-10-20 Chengjie Zhang , Sixia Yu , Qing Chen , Haidong Yuan , C. H. Oh

We propose a family of lower bounds for concurrence in quantum systems using mutually unbiased measurements, which prove more effective in entanglement estimation compared to existing methods. Through analytical and numerical examples, we…

Quantum Physics · Physics 2025-04-22 Yu Lu , Meng Su , Zhong-Xi Shen , Hong-Xing Wu , Shao-Ming Fei , Zhi-Xi Wang

We study the concurrence of arbitrary-dimensional multipartite quantum states. Analytical lower bounds of concurrence for tripartite quantum states are derived by projecting high-dimensional states to $2\otimes 2\otimes 2$ substates. The…

Quantum Physics · Physics 2020-06-16 Hui Zhao , MeiMing Zhang , Shao-Ming Fei , Naihuan Jing

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 obtain an analytical lower bound of entanglement quantified by concurrence for arbitrary bipartite quantum states. It is shown that our bound is tight for some mixed states and is complementary to the previous known lower bounds. On the…

Quantum Physics · Physics 2009-01-24 Yong-Cheng Ou , Heng Fan , Shao-Ming Fei

Quantum entanglement plays a pivotal role in quantum information processing. Quantifying quantum entanglement is a challenging and essential research area within the field. This manuscript explores the relationships between bipartite…

Quantum Physics · Physics 2025-04-22 Ming Li , Yaru Dong , Ruiqi Zhang , Xuena Zhu , Shuqian Shen , Lei Li , Shao-Ming Fei