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We study the process of assisted work distillation. This scenario arises when two parties share a bipartite quantum state $\rho_{AB}$ and their task is to locally distil the optimal amount of work when one party is restricted to thermal…

Quantum Physics · Physics 2019-04-10 Benjamin Morris , Ludovico Lami , Gerardo Adesso

We investigate the problem of copying pure two-qubit states of a given degree of entanglement in an optimal way. Completely positive covariant quantum operations are constructed which maximize the fidelity of the output states with respect…

Quantum Physics · Physics 2009-11-10 J. Novotny , G. Alber , I. Jex

Bounds analogous to entropic uncertainty relations allow one to design practical tests to detect quantum entanglement by a collective measurement performed on several copies of the state analyzed. This approach, initially worked out for…

Quantum Physics · Physics 2013-01-04 Łukasz Rudnicki , Zbigniew Puchała , Paweł Horodecki , Karol Życzkowski

Quantum technologies lead to a variety of applications that outperform their classical counterparts. In order to build a quantum device it must be verified that it operates below some error threshold. Recently, because of technological…

We propose a scheme for both distilling and quantifying entanglement, applicable to individual copies of an arbitrary unknown two-qubit state. It is realized in a usual two-qubit interferometry with local filtering. Proper filtering…

Quantum Physics · Physics 2010-06-09 S. -S. B. Lee , H. -S. Sim

The distribution of entangled states of light over long distances is a major challenge in the field of quantum information. Optical losses, phase diffusion and mixing with thermal states lead to decoherence and destroy the non-classical…

Sharing genuine multipartite entanglement by considering collective use of copies of biseparable states, which are entangled across all bipartitions but lack genuine multipartite entanglement at the single-copy level, plays a central role…

Quantum Physics · Physics 2026-01-26 Swati Choudhary , Ujjwal Sen , Saronath Halder

We experimentally generate and tomographically characterize a mixed, genuinely non-Gaussian bipartite continuous-variable entangled state. By testing entanglement in 2$\times$2-dimensional two-qubit subspaces, entangled qubits are localized…

Quantum Physics · Physics 2015-03-17 T. Kiesel , W. Vogel , B. Hage , R. Schnabel

We analytically obtain the maximum probability of converting a finite number of copies of an arbitrary two-qubit pure state to a single copy of a maximally entangled two-qubit pure state via entanglement assisted local operations and…

Quantum Physics · Physics 2020-07-22 Siddhartha Santra , Vladimir S. Malinovsky

Even though entanglement is very vulnerable to interactions with the environment, it can be created by purely dissipative processes. Yet, the attainable degree of entanglement is profoundly limited in the presence of noise sources. We show…

Quantum Physics · Physics 2013-05-29 Karl Gerd H. Vollbrecht , Christine A. Muschik , J. Ignacio Cirac

High-fidelity entanglement shared between distant quantum systems is an essential resource for quantum communication and computation. Entanglement distillation addresses this need by converting multiple noisy Bell pairs into fewer…

Quantum Physics · Physics 2025-03-14 Shoham Jacoby , Rotem Arnon-Friedman , Serge Rosenblum

Entanglement distillation is the process of converting noisy entangled states into maximally entangled pure states via local operations and classical communication. A long-standing, unresolved question is which entangled states are amenable…

Quantum Physics · Physics 2026-04-28 Tobias C. Sutter , Christopher Popp , Beatrix C. Hiesmayr

A simple scheme to prepare an entanglement between two separated qubits from a given mixed state is proposed. A single qubit (entanglement mediator) is repeatedly made to interact locally and consecutively with the two qubits through…

Quantum Physics · Physics 2007-05-23 Kazuya Yuasa , Hiromichi Nakazato

No pure entangled state can be distilled from a $2\otimes 2$ or $2\otimes 3$ mixed state by separable operations. In $3\otimes 3$, pure entanglement can be distilled by separable operation but not by LOCC. In this letter, we proved the…

Quantum Physics · Physics 2025-08-21 Indranil Biswas , Atanu Bhunia , Indrani Chattopadhyay , Debasis Sarkar

The entanglement of a pure state of a pair of quantum systems is defined as the entropy of either member of the pair. The entanglement of formation of a mixed state is defined as the minimum average entanglement of an ensemble of pure…

Quantum Physics · Physics 2009-01-23 William K. Wootters

We prove that all inseparable Gaussian states of two modes can be distilled into maximally entangled pure states by local operations. Using this result we show that a bipartite Gaussian state of arbitrarily many modes can be distilled if…

Quantum Physics · Physics 2013-05-29 G. Giedke , L. -M. Duan , J. I. Cirac , P. Zoller

We show that any bipartite quantum state of rank four is distillable, when the partial transpose of the state has at least one negative eigenvalue, i.e., the state is NPT. For this purpose we prove that if the partial transpose of a…

Quantum Physics · Physics 2017-10-12 Lin Chen , Dragomir Z Djokovic

We propose a scheme of multipartite entanglement distillation driven by a complementary pair of stabilizer measurements, to distill directly a wider range of states beyond the stabilizer code states (such as the Greenberger-Horne-Zeilinger…

Quantum Physics · Physics 2007-05-23 Akimasa Miyake , Hans J. Briegel

Quantum entanglement is essential to the development of quantum computation, communications, and technology. The controlled SWAP test, widely used for state comparison, can be adapted to an efficient and useful test for entanglement of a…

Quantum Physics · Physics 2022-01-12 Steph Foulds , Viv Kendon , Tim Spiller

Distillation of entanglement using only Gaussian operations is an important primitive in quantum communication, quantum repeater architectures, and distributed quantum computing. Existing distillation protocols for continuous degrees of…

Quantum Physics · Physics 2013-05-30 Earl T. Campbell , Jens Eisert