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We find the necessary and sufficient condition under which two two-qubit mixed states can be purified into a pure maximally entangled state by local operations and classical communication. The optimal protocol for such transformation is…

Quantum Physics · Physics 2007-05-23 Enric Jane

The effect of filtering operation with respect to purification and concentration of entanglement in quantum states are discussed in this paper. It is shown, through examples, that the local action of the filtering operator on a part of the…

Quantum Physics · Physics 2014-05-14 K. O. Yashodamma , P. J. Geetha , Sudha

Quantum error mitigation is essential for computing on the noisy quantum computer with a limited number of qubits. In this paper, we propose a practical protocol of error mitigation by virtually purifying the quantum state without qubit…

Quantum Physics · Physics 2022-03-02 Mingxia Huo , Ying Li

The efficient and reliable characterization of quantum states plays a vital role in most, if not all, quantum information processing tasks. In this work, we present a universally optimal protocol for verifying entangled states by employing…

Quantum Physics · Physics 2021-03-08 Ye-Chao Liu , Jiangwei Shang , Rui Han , Xiangdong Zhang

We investigate entanglement of purification in conformal field theory. By using Reeh-Schlieder theorem, we construct a set of the purification states for $\rho_{AB}$, where $\rho_{AB}$ is reduced density matrix for subregion $AB$ of a…

High Energy Physics - Theory · Physics 2019-09-18 Wu-zhong Guo

Quantum channels generally reduce the distinguishability of quantum states, limiting information transmission and processing. Previous work introduced a protocol capable of increasing the distinguishability of states after the action of a…

Quantum Physics · Physics 2026-05-08 Gabriel M. Arantes , Barbara Amaral , Nadja K. Bernardes

We first propose a novel criterion that guarantees that an $s$-sparse signal is the local minimizer of the $\ell_1/\ell_2$ objective; our criterion is interpretable and useful in practice. We also give the first uniform recovery condition…

Numerical Analysis · Mathematics 2021-01-29 Yiming Xu , Akil Narayan , Hoang Tran , Clayton G. Webster

States of sufficiently low purity are separable and cannot be entangled by unital (purity-non-generating) operations. Since high-purity states are experimentally demanding, it is natural to ask how much purity a state must possess to enable…

We consider an arbitrary qubit channel depending on a single parameter, which is to be estimated by a physical process. Using the quantum Fisher information per channel invocation to quantify the estimation accuracy, we consider various…

Quantum Physics · Physics 2019-02-06 David Collins

Optimisation problems in science and engineering typically involve finding the ground state (i.e. the minimum energy configuration) of a cost function with respect to many variables. If the variables are corrupted by noise then this…

Quantum Physics · Physics 2016-03-08 Nicholas Chancellor , Szilard Szoke , Walter Vinci , Gabriel Aeppli , Paul A. Warburton

Distillation protocols enable generation of high quality entanglement even in the presence of noise. Existing protocols ignore the presence of local information in mixed states produced from some noise sources such as photon loss, amplitude…

Quantum Physics · Physics 2010-07-12 Earl T. Campbell

Uncertainty is an important feature of dynamic systems, and entropy has been widely used to measure this attribute. In this Letter, we prove that state aggregation and decomposition can decrease and increase the entropy, respectively, of…

Information Theory · Computer Science 2022-05-18 Lirong Cui , Xiangchen Li , Narayanaswamy Balakrishnan

We present two quantum state sharing protocols where the channels are not maximally entangled states. By properly choosing the measurement basis it is possible to achieve unity fidelity transfer of the state if the parties collaborate. We…

Quantum Physics · Physics 2009-11-13 Goren Gordon , Gustavo Rigolin

We develop theoretical and numerical tools for the quantification of entanglement in systems with continuous degrees of freedom. Continuous variable entanglement swapping is introduced and based on this idea we develop methods of…

Quantum Physics · Physics 2009-10-31 S. Parker , S. Bose , M. B. Plenio

We consider a class of correlation measures for quantum states called optimized correlation measures, defined as a minimization of a linear combination of von Neumann entropies over purifications of a given state. Examples include the…

High Energy Physics - Theory · Physics 2020-03-13 Newton Cheng

Impressive progress has been made in the past decade in the study of technological applications of varied types of quantum systems. With industry giants like IBM laying down their roadmap for scalable quantum devices with more than…

Quantum Physics · Physics 2021-09-15 Rishabh Gupta , Sabre Kais , Raphael D. Levine

We propose a new approach to the problem of defining the degree of entanglement between two particles in a pure state with Hilbert spaces of arbitrary finite dimensions. The central idea is that entanglement gives rise to correlations…

Quantum Physics · Physics 2007-05-23 Markus A. Cirone

Entanglement purification protocols are fundamental primitives in quantum communication, enabling the distillation of high-quality entanglement using only local operations and classical communication. For large multipartite states, however,…

Quantum Physics · Physics 2026-04-06 Katerina Stloukalova , Jorge Miguel-Ramiro , Wolfgang Dür , Julius Wallnöfer

We construct new entanglement distillation protocols by interpolating between the recurrence and hashing protocols. This leads to asymptotic two-way distillation protocols, resulting in an improvement of the distillation rate for all mixed…

Quantum Physics · Physics 2009-11-10 Karl Gerd H. Vollbrecht , Frank Verstraete

Quantum-limited amplifiers increase the amplitude of quantum signals at the price of introducing additional noise. Quantum purification protocols operate in the reverse way, by reducing the noise while attenuating the signal. Here we…

Quantum Physics · Physics 2017-04-12 Xiaobin Zhao , Giulio Chiribella