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Related papers: The exact convex roof for GHZ-W mixtures for three…

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We explore the dual problem of the convex roof construction by identifying it as a linear semi-infinite programming (LSIP) problem. Using the LSIP theory, we show the absence of a duality gap between primal and dual problems, even if the…

Quantum Physics · Physics 2021-08-25 Thiago Mureebe Carrijo , Wesley Bueno Cardoso , Ardiley Torres Avelar

We study the loss of entanglement of bipartite state subjected to discarding or measurement of one qubit. Examining the behavior of different entanglement measures, we find that entanglement of formation, entanglement cost, and logarithmic…

Quantum Physics · Physics 2009-11-10 Karol Horodecki , Michal Horodecki , Pawel Horodecki , Jonathan Oppenheim

The primary goal in the study of entanglement as a resource theory is to find conditions that determine when one quantum state can or cannot be transformed into another via local operations and classical communication. This is typically…

Quantum Physics · Physics 2017-01-19 Mark W. Girard , Gilad Gour

We give a complete solution for the three-tangle of mixed three-qubit states composed of a generalized GHZ state, a|000>+b|111>, and a generalized W state, c|001>+d|010>+f|100>. Using the methods introduced by Lohmayer et al. we provide…

Quantum Physics · Physics 2009-01-06 Christopher Eltschka , Andreas Osterloh , Jens Siewert , Armin Uhlmann

Characterization of the multipartite mixed state entanglement is still a challenging problem. Since due to the fact that the entanglement for the mixed states, in general, is defined by a convex-roof extension. That is the entanglement…

Quantum Physics · Physics 2016-11-30 M. A. Jafarizadeh , M. Yahyavi , A. Heshmati , N. Karimi , A. Mohamadzadeh , F. Eghbalifam , S. Nami

An important problem in quantum information theory is the quantification of entanglement in multipartite mixed quantum states. In this work, a connection between the geometric measure of entanglement and a distance measure of entanglement…

Quantum Physics · Physics 2010-12-08 Alexander Streltsov , Hermann Kampermann , Dagmar Bruß

We show that when N>>1 the geometric entanglement measure of general N-qubit W states, except maximally entangled W states, is a one-variable function and depends only on the Bloch vector with the minimal z component. Hence one can prepare…

Quantum Physics · Physics 2010-08-12 Levon Tamaryan , Zaruhi Ohanyan , Sayatnova Tamaryan

Multipartite entanglement underpins quantum technologies but its study is limited by the lack of universal measures, unified frameworks, and the intractability of convex-roof extensions. We establish an axiomatic framework and introduce the…

Quantum Physics · Physics 2025-12-16 Jie Guo , Shuyuan Yang , Jinchuan Hou , Xiaofei Qi , Kan He

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

The two-qubit pure state is explicitly parameterized by three unit 2-spheres and a phase factor. For separable states, two of the three unit spheres are the Bloch spheres of each qubit. The third sphere parameterizes the degree and phase of…

Quantum Physics · Physics 2019-07-23 Chu-Ryang Wie

We explore the polytope structures for genuine entanglement, biseparability, full biseparability and Bell inequality of multi-qubit GHZ diagonal states. We first show that biseparable GHZ diagonal states make hypersimplices inside the…

Quantum Physics · Physics 2021-11-17 Kyung Hoon Han , Seung-Hyeok Kye

Convex roof extensions are widely used to create entanglement measures in quantum information theory. The aim of the article is to present some tools which could be helpful for their treatment. Sections 2 and 3 introduce into the subject.…

Quantum Physics · Physics 2011-09-07 Armin Uhlmann

New measures of multipartite entanglement are constructed based on two definitions of multipartite information and different methods of optimizing over extensions of the states. One is a generalization of the squashed entanglement where one…

Quantum Physics · Physics 2016-11-18 Dong Yang , Karol Horodecki , Michal Horodecki , Pawel Horodecki , Jonathan Oppenheim , Wei Song

In this paper, we investigate the convex roof measure of quantum coherence, with a focus on their superadditive properties. We propose sufficient conditions and establish a framework for coherence superadditivity in tripartite and…

Quantum Physics · Physics 2025-05-20 Honglin Ren , Lin Chen

Gudder, in a recent paper, defined a candidate entanglement measure which is called the entanglement number. The entanglement number is first defined on pure states and then it extends to mixed states by the convex roof construction. In…

Quantum Physics · Physics 2023-03-02 George Androulakis , Ryan McGaha

We investigate the evolution of entanglement in the Fenna-Matthew-Olson (FMO) complex based on simulations using the scaled hierarchy equation of motion (HEOM) approach. We examine the role of multipartite entanglement in the FMO complex by…

Chemical Physics · Physics 2012-08-23 Jing Zhu , Sabre Kais , Alán Aspuru-Guzik , Sam Rodriques , Ben Brock , Peter J. Love

We review some properties of the convex roof extension, a construction used, e.g., in the definition of the entanglement of formation. Especially we consider the use of symmetries of channels and states for the construction of the convex…

Quantum Physics · Physics 2012-06-28 Meik Hellmund

We show that any measure of entanglement that on pure bipartite states is given by a strictly concave function of the reduced density matrix is monogamous on pure tripartite states. This includes the important class of bipartite measures of…

Quantum Physics · Physics 2019-04-10 Yu Guo , Gilad Gour

We provide methods for computing the geometric measure of entanglement for two families of pure states with both experimental and theoretical interests: symmetric multiqubit states with non-negative amplitudes in the Dicke basis and…

Quantum Physics · Physics 2012-04-20 Lin Chen , Aimin Xu , Huangjun Zhu

Mixed states appear naturally in experiment over pure states. So for studying different notions of nonlocality and their relation with entanglement in realistic scenarios, one needs to consider mixed states. In a recent article [Phys. Rev.…

Quantum Physics · Physics 2016-09-14 Biswajit Paul , Kaushiki Mukherjee , Debasis Sarkar