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Reversible work extraction from identical quantum systems via collective operations was shown to be possible even without producing entanglement among the sub-parts. Here, we show that implementing such global operations necessarily imply…

Quantum Physics · Physics 2015-03-31 Gian Luca Giorgi , Steve Campbell

Maximally entangled bipartite unitary operators or gates find various applications from quantum information to being building blocks of minimal models of many-body quantum chaos, and have been referred to as "dual unitaries". Dual unitary…

Quantum Physics · Physics 2020-08-19 Suhail Ahmad Rather , S. Aravinda , Arul Lakshminarayan

The emergence of classical world from underlying quantum mechanics is characterized by not only vanishing quantum correlations but also an unfolding of objectivity also known as quantum Darwinism. We show that the absence of this…

Quantum Physics · Physics 2025-10-06 Bishal Kumar Das , Sourav Manna , Vaibhav Madhok

Entanglement is an useful resource because some global operations cannot be locally implemented using classical communication. We prove a number of results about what is and is not locally possible. We focus on orthogonal states, which can…

Quantum Physics · Physics 2009-11-07 Jonathan Walgate , Lucien Hardy

Quantum correlations characterized by quantum entanglement and quantum discord play important roles in many quantum information processing. We study the relations among the entanglement of formation, concurrence, tangle, linear entropy…

Quantum Physics · Physics 2018-08-03 Xue-Na Zhu , Shao-Ming Fei , Xianqing Li-Jost

Classical and quantum world views differ in peculiar ways. Understanding decisive quantum features -- for which no classical explanation exist -- and their interrelations is of foundational interest. Moreover, recognizing non-classical…

Quantum Physics · Physics 2013-11-11 A R Usha Devi , A K Rajagopal , Sudha , H S Karthik , J Prabhu Tej

This article comprehensively explores matrices and their prerequisites for achieving positive semidefiniteness. The study delves into a series of theorems concerning pure quantum states in the context of weighted graphs. The main objective…

Quantum Physics · Physics 2024-11-21 Anoopa Joshi , Parvinder Singh , Atul Kumar

We present computable criterion for completely classifying multi-qubit quantum states under local unitary operations. The criterion can be used to detect whether two quantum states in multi-qubit systems are local unitary equivalent or not.…

Quantum Physics · Physics 2014-06-25 Ming Li , Tinggui Zhang , Shao-Ming Fei , Xianqing Li-Jost , Naihuan Jing

The notion of antidistinguishability captures the possibility of ruling out certain alternatives in a quantum experiment without identifying the actual outcome. Although extensively studied for quantum states, the antidistinguishability of…

Quantum Physics · Physics 2026-03-03 Satyaki Manna , Anandamay Das Bhowmik

Quantum discord (QD) reveals the nonclassical nature of correlations in bipartite quantum states, going beyond the entanglement-separability paradigm. In this article we discuss the suitability of QD in what concern its possible asymmetry…

Quantum Physics · Physics 2015-03-14 J. Maziero , L. C. Celeri , R. M. Serra

Recently, a framework was established to systematically construct novel universal resource states for measurement-based quantum computation using techniques involving finitely correlated states. With these methods, universal states were…

Quantum Physics · Physics 2009-08-04 J. -M. Cai , W. Dür , M. Van den Nest , A. Miyake , H. J. Briegel

Universality is a powerful concept, which enables making qualitative and quantitative predictions in systems with extensively many degrees of freedom. It finds realizations in almost all branches of physics, including in the realm of…

Statistical Mechanics · Physics 2026-05-07 Lukas M. Sieberer , Michael Buchhold , Jamir Marino , Sebastian Diehl

We investigated the super quantum discord based on weak measurements. The super quantum discord is an extension of the standard quantum discord defined by projective measurements and also describes the quantumness of correlations. We…

Quantum Physics · Physics 2014-04-02 Bo Li , Lin Chen , Heng Fan

We discuss a model for quantum computing with initially mixed states. Although such a computer is known to be less powerful than a quantum computer operating with pure (entangled) states, it may efficiently solve some problems for which no…

Quantum Physics · Physics 2015-03-17 Michael Siomau , Stephan Fritzsche

We construct a single observable measurement of which mean value on four copies of an {\it unknown} two-qubit state is sufficient for unambiguous decision whether the state is separable or entangled. In other words, there exists a universal…

Quantum Physics · Physics 2015-06-26 Remigiusz Augusiak , Maciej Demianowicz , Pawel Horodecki

Unambiguous discrimination and exact cloning reduce the square-overlap between quantum states, exemplifying the more general type of procedure we term state separation. We obtain the maximum probability with which two equiprobable quantum…

Quantum Physics · Physics 2008-11-26 Anthony Chefles , Stephen M. Barnett

We show that the phenomenon of frozen discord, exhibited by specific classes of two-qubit states under local nondissipative decoherent evolutions, is a common feature of all known bona fide measures of general quantum correlations. All…

Quantum Physics · Physics 2013-07-23 Benjamin Aaronson , Rosario Lo Franco , Gerardo Adesso

Quantum processes can be divided into two categories: unitary and non-unitary ones. For a given quantum process, we can define a \textit{degree of the unitarity (DU)} of this process to be the fidelity between it and its closest unitary…

Quantum Physics · Physics 2015-06-19 Jing-Xin Cui , Z. D. Wang

We show that any two different unitary operations acting on an arbitrary multipartite quantum system can be perfectly distinguishable by local operations and classical communication when a finite number of runs is allowed. We then directly…

Quantum Physics · Physics 2011-11-09 Runyao Duan , Yuan Feng , Mingsheng Ying

To quantify single mode nonclassicality, we start from an operational approach. A positive semi-definite observable is introduced to describe a measurement setup. The quantification is based on the negativity of the normally ordered version…

Quantum Physics · Physics 2012-11-29 C. Gehrke , J. Sperling , W. Vogel