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Related papers: Separable states to distribute entanglement

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The state of an entangled q-bit pair is specified by 15 numerical parameters that are naturally regarded as the components of two 3-vectors and a $3\times3$-dyadic. There are easy-to-use criteria to check whether a given pair of 3-vectors…

Quantum Physics · Physics 2015-06-26 Berthold-Georg Englert , Nasser Metwally

It is known that $\rho^{AB}$ as a bipartite reduced state of the 3-qubit GHZ state is separable, but part $A$ and part $B$ indeed ``share tripartite entanglement'' in the GHZ state. Namely, whether a state can ``share'' more entanglement is…

Quantum Physics · Physics 2025-12-01 Yu Guo , Ning Yang

We report observations of entanglement of two remote atomic qubits, achieved by generating an entangled state of an atomic qubit and a single photon at Site A, transmitting the photon to Site B in an adjacent laboratory through an optical…

Quantum Physics · Physics 2009-11-11 D. N. Matsukevich , T. Chaneliere , S. D. Jenkins , S. -Y. Lan , T. A. B. Kennedy , A. Kuzmich

We discuss the concept of how entanglement changes with respect to different factorizations of the total algebra which describes the quantum states. Depending on the considered factorization a quantum state appears either entangled or…

Quantum Physics · Physics 2011-11-15 Walter Thirring , Reinhold A. Bertlmann , Philipp Köhler , Heide Narnhofer

We characterize the multipartite entanglement of a system of n qubits in terms of the distribution function of the bipartite purity over balanced bipartitions. We search for maximally multipartite entangled states, whose average purity is…

Quantum Physics · Physics 2015-03-13 P. Facchi , G. Florio , U. Marzolino , G. Parisi , S. Pascazio

A 6-qubit hyperentangled state has been realized by entangling two photons in three degrees of freedom. These correspond to the polarization, the longitudinal momentum and the indistinguishable emission produced by a 2-crystal system…

Quantum Physics · Physics 2009-09-29 G. Vallone , R. Ceccarelli , F. De Martini , P. Mataloni

We study the fully entangled fraction of quantum states. An upper bound is obtained for arbitrary dimensional bipartite systems. This bound is shown to be exact for the case of two-qubit systems. An inequality related the fully entangled…

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

Motivated by the mathematical definition of entanglement we undertake a rigorous analysis of the separability and non-distillability properties in the neighborhood of those three-qubit mixed states which are entangled and completely…

Quantum Physics · Physics 2009-11-10 Roman Orus , Rolf Tarrach

Two qubits is the simplest system where the notions of separable and entangled states and entanglement witnesses first appear. We give a three dimensional geometric description of these notions. This description however carries no…

Quantum Physics · Physics 2014-07-22 J. E. Avron , O. Kenneth

Singlet-triplet states in double quantum dots are promising realizations of qubits, and capacitive coupling can be used to create entanglement between these qubits. We propose an entangling three-qubit gate of singlet-triplet qubits in a…

Mesoscale and Nanoscale Physics · Physics 2014-05-05 Tuukka Hiltunen , Ari Harju

Understanding what can be inferred about a multi-particle quantum system from only the knowledge of its subparts is a highly non-trivial task. Clearly, if the global system doesn't contain any information resource, nor do its subparts.…

Quantum Physics · Physics 2013-05-30 Lars Erik Würflinger , Jean-Daniel Bancal , Antonio Acín , Nicolas Gisin , Tamas Vertesi

We find a coupling-strength configuration for a linear chain of N spins which gives rise to simultaneous multiple Bell states. We suggest a way such an interesting entanglement pattern can be used in order to distribute maximally entangled…

Quantum Physics · Physics 2008-03-02 C. Di Franco , M. Paternostro , M. S. Kim

Based on the mutually unbiased bases, the mutually unbiased measurements and the general symmetric informationally complete positive-operator-valued measures, we propose three separability criteria for $d$-dimensional bipartite quantum…

Quantum Physics · Physics 2015-09-02 Shu-Qian Shen , Ming Li , Xue-Feng Duan

Consider a ring of N qubits in a translationally invariant quantum state. We ask to what extent each pair of nearest neighbors can be entangled. Under certain assumptions about the form of the state, we find a formula for the maximum…

Quantum Physics · Physics 2009-11-06 Kevin M. O'Connor , William K. Wootters

We present a method to derive separability criteria for the different classes of multiparticle entanglement, especially genuine multiparticle entanglement. The resulting criteria are necessary and sufficient for certain families of states.…

Quantum Physics · Physics 2010-05-07 Otfried Gühne , Michael Seevinck

A mixed quantum state shared between two parties is said to be distillable if, by means of a protocol involving only local quantum operations and classical communication, the two parties can transform some number of copies of that state…

Quantum Physics · Physics 2009-11-10 John Watrous

While the concept of entanglement for distinguishable particles is well established, defining entanglement and non-locality in systems of indistinguishable particles, which require the use of the (anti)symmetrization postulate, remains…

Quantum Physics · Physics 2025-04-10 P. Céspedes , F. H. Holik , A. P. Majtey

In [Science 340, 1205, 7 June (2013)], via polytopes Michael Walter et al. proposed a sufficient condition detecting the genuinely entangled pure states. In this paper, assume that a state with six non-zero coefficients is not a trivially…

Quantum Physics · Physics 2025-10-21 Dafa Li

We investigate the process of entanglement transfer from a three-mode quantized field to a system of three spatially separated qubits each one made of a two-level atom resonantly coupled to a cavity mode. The optimal conditions for…

Quantum Physics · Physics 2009-11-13 Federico Casagrande , Alfredo Lulli , Matteo G. A. Paris

Shared entanglement between spatially separated systems is an essential resource for quantum information processing including long-distance quantum cryptography and teleportation. While purification protocols for mixed distributed entangled…

Quantum Physics · Physics 2017-08-30 Jennifer R. Glick , Christoph Adami