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The quantum discord is used as measure of quantum correlations for two families of multipartite coherent states. The first family interpolates between generalized GHZ states and generalized Werner states. The second one is an interpolation…

Quantum Physics · Physics 2012-11-01 M. Daoud , R. Ahl Laamara

We study the level surfaces of quantum discord for a class of two-qubit states with parallel nonzero Bloch vectors. The dynamic behavior of quantum discord under decoherence is investigated. It is shown that a class of X states has sudden…

Quantum Physics · Physics 2011-04-12 Bo Li , Zhi-Xi Wang , Shao-Ming Fei

We consider the quantum discord in a two-particle spin-1/2 system (dimer) governed by the standard multiple quantum (MQ) Hamiltonian and reveal the relation between the discord and the intensity of the second-order MQ coherence. Since the…

Quantum Physics · Physics 2015-05-30 E. I. Kuznetsova , A. I. Zenchuk

We give a new separability criterion, a necessary condition for separability of $N$-partite quantum states. The criterion is based on the Bloch representation of a $N$-partite quantum state and makes use of multilinear algebra, in…

Quantum Physics · Physics 2008-07-17 Ali Saif M. Hassan , Pramod S. Joag

We identify the families of states that maximise some recently proposed quantifiers of Einstein-Podolsky-Rosen (EPR) steering and the volume of the Quantum Steering Ellipsoid (QSE). The optimal measurements which maximise genuine EPR…

Quantum Physics · Physics 2017-01-23 R. McCloskey , A. Ferraro , M. Paternostro

The quantum discrimination of two non-coherent states draws much attention recently. In this letter, we first consider the quantum discrimination of two noiseless displaced number states. Then we derive the Fock representation of noisy…

Quantum Physics · Physics 2020-12-10 Renzhi Yuan , Julian Cheng

The geometric quantum discord of a two-qudit state has been studied in many papers, however, its exact analytical value in the explicit form is known only for a general two-qubit state, a general qubit-qudit state and some special families…

Quantum Physics · Physics 2024-09-24 Elena R. Loubenets , Louis Hanotel

When quantum states are used to send classical information, the receiver performs a measurement on the signal states. The amount of information extracted is often not optimal due to the receiver's measurement scheme and experimental…

Quantum Physics · Physics 2018-04-25 Rui Han , Gerd Leuchs , Markus Grassl

Distinguishing physical processes is one of the fundamental problems in quantum physics. Although distinguishability of quantum preparations and quantum channels have been studied considerably, distinguishability of quantum measurements…

Quantum Physics · Physics 2021-04-13 Chandan Datta , Tanmoy Biswas , Debashis Saha , Remigiusz Augusiak

The optimal state determination (or tomography) is studied for a composite system of two qubits when measurements can be performed on one of the qubits and interactions of the two qubits can be implemented. The goal is to minimize the…

Quantum Physics · Physics 2009-11-13 D. Petz , K. M. Hangos , A. Szanto , F. Szollosi

We relate the the distinguishability of quantum states with their robustness of the entanglement, where the robustness of any resource quantifies how tolerant it is to noise. In particular, we identify upper and lower bounds on the…

Quantum Physics · Physics 2025-12-24 Debarupa Saha , Kornikar Sen , Chirag Srivastava , Ujjwal Sen

We propose a method to verify quantum steering for two qubit states with an arbitrary amount of null results when both the steering and steered parties cannot be trusted. We converted the steering inequality proposed in a recent article…

Quantum Physics · Physics 2019-01-16 InU Jeon , Hyunseok Jeong

We highlight an information-theoretic meaning of quantum discord as the gap between the ac- cessible information and the Holevo bound in the framework of ensemble of quantum states. This complementary relationship implies that a large…

Quantum Physics · Physics 2013-03-21 Yao Yao , Jing-Zheng Huang , Xu-Bo Zou , Zhen-Qiang Yin , Wei Chen , Guang-Can Guo , Zheng-Fu Han

Recently, a basis-invariant measure of coherence known as the intrinsic degree of coherence has been established for classical and single-particle quantum states [JOSA B {\bf 36}, 2765 (2019)]. Using the same mathematical construction, in…

Quantum Physics · Physics 2020-03-30 Nilakantha Meher , Abu Saleh Musa Patoary , Girish Kulkarni , Anand K. Jha

Quantum discord, as introduced by Olliver and Zurek [Phys. Rev. Lett. \textbf{88}, 017901 (2001)], is a measure of the discrepancy between quantum versions of two classically equivalent expressions for mutual information and is found to be…

Quantum Physics · Physics 2015-06-04 Ali Saif M. Hassan , Pramod S. Joag

The Hilbert-Schmidt distance between a mixed three-qubit state and its closest state is used to quantify the amount of pairwise quantum correlations in a tripartite system. Analytical expressions of geometric quantum discord are derived. A…

Quantum Physics · Physics 2016-01-20 M. Daoud , R. Ahl Laamara , S. Seddik

We investigate the disappearance of discord in 2- and multi-qubit systems subject to decohering influences. We formulate the computation of quantum discord in terms of the generalized Bloch vector, which gives useful insights on the time…

Quantum Physics · Physics 2014-04-21 Hyungjun Lim , Robert Joynt

The quantum steering ellipsoid (QSE) provides a geometric representation, within the Bloch picture, of all possible states to which one qubit can be steered through measurements performed on another correlated qubit. However, in most…

Quantum Physics · Physics 2026-02-12 Wen-Jie Zhang , Jun-Hong An

We consider the problem of $1$-sided device-independent self-testing of any pure entangled two-qubit state based on steering inequalities which certify the presence of quantum steering. In particular, we note that in the $2-2-2$ steering…

We devise and experimentally realize a procedure capable of detecting and distinguishing quantum discord and classical correlations as well the presence of factorized states in a joint system-environment setting. Our scheme builds on recent…

Quantum Physics · Physics 2014-11-14 Simone Cialdi , Andrea Smirne , Matteo G. A. Paris , Stefano Olivares , Bassano Vacchini