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In the past decades, quantum entanglement has been recognized to be the basic resource in quantum information theory. A fundamental need is then the understanding its qualification and its quantification: Is the quantum state entangled, and…

Quantum Physics · Physics 2013-02-20 Szilárd Szalay

The majorization relation has been shown to be useful in classifying which transformations of jointly held quantum states are possible using local operations and classical communication. In some cases, a direct transformation between two…

Quantum Physics · Physics 2013-05-29 Sumit Daftuar , Matthew Klimesh

We find that the mixed maximally entangled states exist and prove that the form of the mixed maximally entangled states is unique in terms of the entanglement of formation. Moreover, even if the entanglement is quantified by other…

Quantum Physics · Physics 2012-02-28 Zong-Guo Li , Ming-Jing Zhao , Shao-Ming Fei , Heng Fan , W. M. Liu

We describe a purely algebraic method for finding the best separable approximation to a mixed state of a composite 2x2 quantum system, consisting of a decomposition of the state into a linear combination of a mixed separable part and a pure…

Quantum Physics · Physics 2009-11-07 Thomas Wellens , Marek Kus

Multipartite entanglement is one of the hallmarks of quantum mechanics and is central to quantum information processing. In this work we show that Concentratable Entanglement (CE), an operationally motivated entanglement measure, induces a…

Quantum Physics · Physics 2024-10-01 Louis Schatzki , Guangkuo Liu , M. Cerezo , Eric Chitambar

In this work, we construct small sets of bipartite orthogonal pure states that cannot be perfectly distinguished by local operations and classical communication (LOCC). We mention that not all the states within the constructed sets are…

Quantum Physics · Physics 2026-03-31 Saronath Halder , Suchetana Goswami

In a multipartite scenario quantum entanglement manifests its most dramatic form when the state is genuinely entangled. Such a state is more beneficial for information theoretic applications if it contains distillable entanglement in every…

Quantum Physics · Physics 2019-03-27 Sristy Agrawal , Saronath Halder , Manik Banik

We characterize the multipartite entanglement of a system of n qubits in terms of the distribution function of the bipartite purity over all balanced bipartitions. We search for those (maximally multipartite entangled) states whose purity…

Quantum Physics · Physics 2010-02-01 Paolo Facchi , Giuseppe Florio , Ugo Marzolino , Giorgio Parisi , Saverio Pascazio

We prove experimentally the predicted existence of a three-qubit quantum state with genuine multipartite entanglement which can be certified solely from its separable two-qubit reduced density matrices. The qubits are encoded into different…

Quantum Physics · Physics 2020-08-05 Michal Mičuda , Robert Stárek , Jan Provazník , Olga Leskovjanová , Ladislav Mišta,

Absolutely Maximally Entangled (AME) states are important resources in quantum information processing; however, a general systematic approach for constructing these states remains a formidable challenge. We identify a finite-field rank…

Quantum Physics · Physics 2026-05-07 Zakaria Dahbi , Amelle Zair

A family of rank-n (n=5,6,7,8) three-qubit mixed states are constructed. The explicit expressions for the three-tangle and optimal decompositions for all these states are given. The CKW relations for these states are also discussed.

Quantum Physics · Physics 2015-05-27 Shu-Juan He , Xiao-Hong Wang , Shao-Ming Fei , Hong-Xiang Sun , Qiao-Yan Wen

Understanding multipartite entanglement is a key goal in quantum information. Entanglement in pure states can be characterised by considering transformations under Local Operations assisted by Classical Communication (LOCC). However, it has…

Quantum Physics · Physics 2024-03-06 David Gunn , Martin Hebenstreit , Cornelia Spee , Julio I. de Vicente , Barbara Kraus

Pure multiparticle quantum states are called absolutely maximally entangled if all reduced states obtained by tracing out at least half of the particles are maximally mixed. We provide a method to characterize these states for a general…

Quantum Physics · Physics 2017-05-19 Felix Huber , Otfried Gühne , Jens Siewert

The newfound importance of ``entanglement as a resource'' in quantum computation and quantum communication compels us to quantify it in as many distinct ways as possible. Here we explore a new measure of entanglement for mixed quantum…

It is known that he bipartite quantum states, with rank strictly smaller than the maximum of the ranks of its two reduced states, are distillable by local operations and classical communication. Our first main result is that this is also…

Quantum Physics · Physics 2015-05-27 Lin Chen , Dragomir Z. Djokovic

Quantities invariant under local unitary transformations are of natural interest in the study of entanglement. This paper deduces and studies a particularly simple quantity that is constructed from a combination of two standard permutations…

Quantum Physics · Physics 2021-08-12 Udaysinh T. Bhosale , Arul Lakshminarayan

Entanglement is defined as presence of quantum correlations beyond those achieved by local action and classical communication. To identify its presence in a generic state, one can, for example, check for existence of a decomposition of…

Quantum Physics · Physics 2024-07-19 Marcin Wieśniak

A systematic method for generating bound entangled states in any bipartite system, with ranks ranging from five to full rank, is presented. These states are constructed by mixing separable states with UPB (Unextendible Product Basis) -…

Quantum Physics · Physics 2009-11-10 Somshubhro Bandyopadhyay , Sibasish Ghosh , Vwani Roychowdhury

We give a criterion for a positive mapping on the space of operators on a Hilbert space to be indecomposable. We show that this criterion can be applied to two families of positive maps. These families of maps can then be used to form…

Quantum Physics · Physics 2007-05-23 William Hall

Entanglement in a class of bipartite generalized coherent states is discussed. It is shown that a positive parameter can be associated with the bipartite generalized coherent states so that the states with equal value for the parameter are…

Quantum Physics · Physics 2009-11-13 S. Sivakumar