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We investigate the effect of a non-uniform deformation applied to one-dimensional (1D) quantum systems, where the local energy scale is proportional to $g_j = [\sin (j \pi / N)]^m$ determined by a positive integer $m$, site index $1 \leq j…

Strongly Correlated Electrons · Physics 2011-05-23 A. Gendiar , M. Daniska , Y. Lee , T. Nishino

A new class of state transformations that are quantum mechanically prohibited is introduced. These can be seen as the generalization of the universal-NOT transformation which, for all pure inputs state of a given Hilbert space produces pure…

Quantum Physics · Physics 2015-06-26 Vittorio Giovannetti , Rosario Fazio

Quantum Discord (QD) is a measure of the total quantum non-local correlations of a quantum system. The formalism of quantum discord has been applied to various two-qubit mixed states and it has been reported that there is a non-zero quantum…

Quantum Physics · Physics 2022-10-04 M. S. Ramkarthik , Devvrat Tiwari , Pranay Barkataki

In conventional Schr\"{o}dinger representation the unitarity of the evolution of bound states is guaranteed by the Hermiticity of the Hamiltonian. A non-unitary isospectral simplification of the Hamiltonian, $\mathfrak{h} \to…

Quantum Physics · Physics 2020-01-13 Miloslav Znojil

Based on the relative entropy, we give a unified characterization of quantum correlations for nonlocality, steerability, discord and entanglement for any bipartite quantum states. For two-qubit states we show that the quantities obtained…

Quantum Physics · Physics 2017-04-14 Tinggui Zhang , Hong Yang , Xianqing Li-Jost , Shao-Ming Fei

In order to resolve the measurement problem of Quantum Mechanics, non-unitary time evolution has been derived from the unitarity of standard quantum formalism. New wave functions of free and non-free quantum systems follow from Schroedinger…

Quantum Physics · Physics 2007-05-23 Pradip Kumar Chatterjee

We prove a tight and close-to-optimal lower bound on the effectiveness of local quantum measurements (without classical communication) at discriminating any two bipartite quantum states. Our result implies, for example, that any two…

Quantum Physics · Physics 2022-10-26 Willian H. G. Corrêa , Ludovico Lami , Carlos Palazuelos

Universality of local unitary transformations is one of the cornerstones of quantum computing with many applications and implications that go beyond this field. However, it has been recently shown that this universality does not hold in the…

Quantum Physics · Physics 2024-05-17 Iman Marvian , Hanqing Liu , Austin Hulse

Quantum entanglement and quantum nonstabilizerness are fundamental resources that characterize distinct aspects of a quantum state: entanglement reflects non-local correlations, while nonstabilizerness quantifies the deviation from…

Quantum Physics · Physics 2025-05-29 Dongheng Qian , Jing Wang

Quantum nonlocality without entanglement (Q-NWE) encapsulates nonlocal behavior of multipartite product states as they may entail global operation for optimal decoding of the classical information encoded within. Here we show that the…

Quantum Physics · Physics 2020-03-25 Some Sankar Bhattacharya , Sutapa Saha , Tamal Guha , Manik Banik

Entanglement is one of the key feature of quantum world and any entanglement measure must satisfy some basic laws. Most important of them is the invariance of entanglement under local unitary operations. We show that this is no longer true…

Quantum Physics · Physics 2014-04-25 Arun Kumar Pati

The symmetric collective states of an atomic spin ensemble (i.e., many-body states that are invariant under particle exchange) are not preserved by decoherence that acts identically but individually on members of the ensemble. We develop a…

Quantum Physics · Physics 2008-05-20 Bradley A. Chase , J. M. Geremia

The statistics of local measurements of joint quantum systems can sometimes be used to distinguish the spatiotemporal structure in which they were measured. We first prove that every bipartite separable density matrix is temporally…

Quantum Physics · Physics 2026-01-05 Minjeong Song , Arthur J. Parzygnat

We investigate evolution of quantum correlations in ensembles of two-qubit nuclear spin systems via nuclear magnetic resonance techniques. We use discord as a measure of quantum correlations and the Werner state as an explicit example. We…

Quantum Physics · Physics 2012-10-31 Hemant Katiyar , Soumya Singha Roy , T. S. Mahesh , Apoorva Patel

We consider the classical correlations that two observers can extract by measurements on a bipartite quantum state, and we discuss how they are related to the quantum mutual information of the state. We show with several examples how…

Quantum Physics · Physics 2009-09-19 Shengjun Wu , Uffe V. Poulsen , Klaus Mølmer

In this work it is shown that there is an inherent nonlinear evolution in the dynamics of the so-called generalized coherent states. To show this, the immersion of a classical manifold into the Hilbert space of quantum mechanics is…

Quantum Physics · Physics 2021-05-05 Hans Cruz-Prado , Giuseppe Marmo , Dieter Schuch , Octavio Castaños

In quantum mechanics, joint measurements of non-commuting observables are only possible if a minimal unavoidable measurement uncertainty is accepted. On the other hand, correlations between non-commuting observables can exceed classical…

Quantum Physics · Physics 2019-07-24 Holger F. Hofmann

There is a natural equivalence relation on representations of the states of a given quantum system in a Hilbert space, two representations being equivalent iff they are related by a unitary transformation. There are two equivalence classes,…

Quantum Physics · Physics 2007-05-23 Robert A. Van Wesep

We study the local indistinguishability problem of quantum states. By introducing an easily calculated quantity, non-commutativity, we present an criterion which is both necessary and sufficient for the local indistinguishability of a…

Quantum Physics · Physics 2014-09-17 Teng Ma , Ming-Jing Zhao , Yao-Kun Wang , Shao-Ming Fei

Quantum nonlocal correlations are generated by implementation of local quantum measurements on spatially separated quantum subsystems. Depending on the underlying mathematical model, various notions of sets of quantum correlations can be…

Quantum Physics · Physics 2021-02-03 Salman Beigi