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We present an approach to purification and entanglement routing on complex quantum network architectures, that is, how a quantum network equipped with imperfect channel fidelities and limited memory storage time can distribute entanglement…

An idea of hybrid maps is proposed to establish standard entanglement purification protocols which guarantee to purify any distillable state to a desired maximally entangled pure state all by the standard purification local operations and…

Quantum Physics · Physics 2009-11-10 Jin-Yuan Hsieh , Che-Ming Li , Der-San Chuu

Quantum entanglement and its paradoxical properties hold the key to an information processing revolution. Much attention has focused recently on the challenging problem of characterizing entanglement. Entanglement for a two qubit system is…

Quantum Physics · Physics 2009-11-07 Vivien M Kendon , Kae Nemoto , William J Munro

We present a new approach to the analysis of entanglement in smooth bipartite continuous-variable states. One or both parties perform projective filterings via preliminary measurements to determine whether the system is located in some…

Quantum Physics · Physics 2009-11-13 H. -C. Lin , A. J. Fisher

A generic scheme for the parametrization of mixed state systems is introduced, which is then adapted to bipartite systems, especially to a 2-qubit system. Various features of 2-qubit entanglement are analyzed based on the scheme. Our…

Quantum Physics · Physics 2022-07-15 Otto C. W. Kong , Hock King Ting

Entanglement purification allows the creation of qubit pairs of arbitrarily high fidelity with respect to a maximally entangled state, starting from a larger number of low-fidelity pairs. Purification requires quantum memory, a role for…

Quantum Physics · Physics 2016-01-20 Adrian Auer , Guido Burkard

We provide generalizations of known two-qubit entanglement distillation protocols for arbitrary Hilbert space dimensions. The protocols, which are analogues of the hashing and breeding procedures, are adapted to bipartite quantum states…

Quantum Physics · Physics 2009-11-07 K. G. H. Vollbrecht , M. M. Wolf

The entanglement resource required for quantum information processing comes in a variety of forms, from Bell states to multipartite GHZ states or cluster states. Purifying these resources after their imperfect generation is an indispensable…

Quantum Physics · Physics 2021-09-09 Stefan Krastanov , Alexander Sanchez de la Cerda , Prineha Narang

The verification of quantum entanglement is essential for quality control in quantum communication. In this work, we propose an efficient protocol to directly verify the two-qubit entanglement of a known target state through a single…

Quantum Physics · Physics 2026-04-22 Ricardo Rodriguez , Nam Nguyen , Elizabeth Behrman , Andrew C. Y. Li , James Steck

We introduce a class of multiparticle entanglement purification protocols that allow us to distill a large class of entangled states. These include cluster states, GHZ states and various error correction codes all of which belong to the…

Quantum Physics · Physics 2009-11-10 W. Dür , H. Aschauer , H. -J. Briegel

Quantum networks rely on the efficient distribution of entanglement to enable long-distance quantum communication and information processing. A key challenge in these networks is the design of routing protocols capable of maintaining high…

Networking and Internet Architecture · Computer Science 2026-05-25 Javier Vecino Peñas , Ana Fernández-Vilas , Rebeca P. Díaz-Redondo , Sergio Gándara Gándara , Manuel Fernández-Veiga

We investigate multiparticle entanglement purification schemes which allow one to purify all two colorable graph states, a class of states which includes e.g. cluster states, GHZ states and codewords of various error correction codes. The…

Quantum Physics · Physics 2016-08-16 H. Aschauer , W. Dür , H. -J. Briegel

Since entanglement is not an observable per se, measuring its value in practice is a difficult task. Here we propose a protocol for quantifying a particular entanglement measure, namely concurrence, of an arbitrary two-qubit pure state via…

Quantum Physics · Physics 2017-05-10 Mikko Tukiainen , Hirokazu Kobayashi , Yutaka Shikano

We study the problem of general entanglement purification protocols. Suppose Alice and Bob share a bipartite state $\rho$ which is ``reasonably close'' to perfect EPR pairs. The only information Alice and Bob possess is a lower bound on the…

Quantum Physics · Physics 2007-05-23 Andris Ambainis , Ke Yang

Entanglement purification and distillation protocols are essential for harnessing the full potential of quantum communication technologies. Multiple strategies have been proposed to approach and optimize such protocols, most however…

Quantum Physics · Physics 2025-04-16 Jorge Miguel-Ramiro , Alexander Pirker , Wolfgang Dür

We give a review on entanglement purification for bipartite and multipartite quantum states, with the main focus on theoretical work carried out by our group in the last couple of years. We discuss entanglement purification in the context…

Quantum Physics · Physics 2009-11-13 W. Dür , H. J. Briegel

We propose an entanglement purification scheme based on material qubits and ancillary coherent multiphoton states. We consider a typical QED scenario where material qubits implemented by two-level atoms fly sequentially through a cavity and…

Quantum Physics · Physics 2016-03-14 József Zsolt Bernád , Juan Mauricio Torres , Ludwig Kunz , Gernot Alber

We introduce a simple, experimentally realisable, entanglement manipulation protocol for exploring mixed state entanglement. We show that for both non-maximally entangled pure, and mixed polarisation-entangled two qubit states, an increase…

Quantum Physics · Physics 2009-11-06 R. T. Thew , W. J. Munro

Quantum Entanglement is a fundamentally important resource in Quantum Information Science; however, generating it in practice is plagued by noise and decoherence, limiting its utility. Entanglement distillation and forward error correction…

Quantum Physics · Physics 2023-07-14 Vaishnavi L. Addala , Shu Ge , Stefan Krastanov

Known entanglement purification protocols for mixed states use collective measurements on several copies of the state in order to increase the entanglement of some of them. We address the question of whether it is possible to purify the…

Quantum Physics · Physics 2009-10-31 N. Linden , S. Massar , S. Popescu