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We consider multipartite quantum state discrimination and show that the minimum-error discrimination by separable measurements is closely related to the concept of entanglement witness. Based on the properties of entanglement witness, we…

Quantum Physics · Physics 2023-04-25 Donghoon Ha , Jeong San Kim

Traditionally, quantum state correlation can be obtained with calculations on a state density matrix already known. Here, we propose a model with which correlations of unknown quantum states can be obtained. There are no needs of classical…

Quantum Physics · Physics 2018-06-18 Hui Li , Yan-Song Li , Chao Zheng , Xian Lu

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

In this paper, we propose and evaluate the performance of a unified computational framework for preconditioning systems of linear equations resulting from the solution of coupled problems with monolithic schemes. The framework is composed…

Numerical Analysis · Mathematics 2016-08-24 Francesc Verdugo , Wolfgang A. Wall

Quantum state discrimination is a fundamental primitive in quantum information processing, underpinning tasks in quantum communication, sensing, and learning. We consider the general Bayes framework, as introduced by Helstrom, for state…

Quantum Physics · Physics 2026-05-01 Ankith Mohan , Jamie Sikora , Sarvagya Upadhyay

We describe a quantum algorithm that generalizes the quantum linear system algorithm [Harrow et al., Phys. Rev. Lett. 103, 150502 (2009)] to arbitrary problem specifications. We develop a state preparation routine that can initialize…

Quantum Physics · Physics 2013-06-25 B. D. Clader , B. C. Jacobs , C. R. Sprouse

We address the following state comparison problem: is it possible to design an experiment enabling us to unambiguously decide (based on the observed outcome statistics) on the sameness or difference of two unknown state preparations without…

Quantum Physics · Physics 2012-06-05 Sergey N. Filippov , Mario Ziman

We provide a categorical notion called uncertain bisimilarity, which allows to reason about bisimilarity in combination with a lack of knowledge about the involved systems. Such uncertainty arises naturally in automata learning algorithms,…

Discrete Mathematics · Computer Science 2023-03-28 Jurriaan Rot , Thorsten Wißmann

We study the problem of whether all bipartite quantum states having a prescribed spectrum remain positive under the reduction map applied to one subsystem. We provide necessary and sufficient conditions, in the form of a family of linear…

Quantum Physics · Physics 2015-03-16 Maria Anastasia Jivulescu , Nicolae Lupa , Ion Nechita , David Reeb

The paper outlines a new development in the Contextuality-by-Default theory as applied to finite systems of binary random variables. The logic and principles of the original theory remain unchanged, but the definition of contextuality of a…

Quantum Physics · Physics 2016-10-26 Ehtibar N. Dzhafarov , Janne V. Kujala

A measurement strategy is developed for a new kind of hypothesis testing. It assigns, with minimum probability of error, the state of a quantum system to one or the other of two complementary subsets of a set of N given non-orthogonal…

Quantum Physics · Physics 2009-11-07 Ulrike Herzog , Janos A. Bergou

We describe a class of programmable devices that can discriminate between two quantum states. We consider two cases. In the first, both states are unknown. One copy of each of the unknown states is provided as input, or program, for the two…

Quantum Physics · Physics 2009-11-13 Janos A. Bergou , Vladimir Buzek , Edgar Feldman , Ulrike Herzog , Mark Hillery

The so-called permutation separability criteria are simple operational conditions that are necessary for separability of mixed states of multipartite systems: (1) permute the indices of the density matrix and (2) check if the trace norm of…

Quantum Physics · Physics 2007-05-23 Pawel Wocjan , Michal Horodecki

We develop a statistical framework, based on a manifold learning embedding, to extract relevant features of multipartite entanglement structures of mixed quantum states from the measurable correlation data of a quantum computer. We show…

Quantum Physics · Physics 2024-07-26 Eric Brunner , Aaron Xie , Gabriel Dufour , Andreas Buchleitner

The notion of semi-classical states is first sharpened by clarifying two issues that appear to have been overlooked in the literature. Systems with linear and quadratic constraints are then considered and the group averaging procedure is…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Abhay Ashtekar , Luca Bombelli , Alejandro Corichi

We investigate unambiguous discrimination between given quantum states with a sequential measurement, which is restricted to local measurements and one-way classical communication. If the given states are binary or those each of whose…

Quantum Physics · Physics 2019-02-18 Kenji Nakahira , Kentaro Kato , Tsuyoshi Sasaki Usuda

Based on the ranks of reduced density matrices, we derive necessary conditions for the separability of multiparticle arbitrary-dimensional mixed states, which are equivalent to sufficient conditions for entanglement. In a similar way we…

Quantum Physics · Physics 2007-05-23 Bo Chong , Hellmut Keiter , Joachim Stolze

We examine two conditions that can be used to detect bipartite entanglement, and show that they can be used to provide lower bounds on the negativity of states. We begin with two-qubit states, and then show how what was done there can be…

Quantum Physics · Physics 2024-02-14 Mark Hillery , Camilla Polvara , Vadim Oganesyan , Nada Ali

Canonical correlation analysis is a statistical technique that is used to find relations between two sets of variables. An important extension in pattern analysis is to consider more than two sets of variables. This problem can be expressed…

Machine Learning · Computer Science 2013-02-06 Jan Rupnik , Primoz Skraba , John Shawe-Taylor , Sabrina Guettes

The design of unknown-input decoupled observers and filters requires the assumption of an existence condition in the literature. This paper addresses an unknown input filtering problem where the existence condition is not satisfied. Instead…

Systems and Control · Computer Science 2020-05-05 Peng Lu , Erik-Jan van Kampen , Cornelis C. de Visser , Qiping Chu