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Related papers: Quantum discord of SU(2) invariant states

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Computing the entanglement of formation of a bipartite state is generally difficult, but special symmetries of a state can simplify the problem. For instance, this allows one to determine the entanglement of formation of Werner states and…

Quantum Physics · Physics 2007-05-23 Kiran K. Manne , Carlton M. Caves

The counterintuitive effect of non-unique ordering of two-qubit states with quantum entanglement measures was discovered over ten years ago. More precisely, it was shown by Monte Carlo simulations that there exist states for which the…

Quantum Physics · Physics 2012-07-17 Małgorzata Okrasa , Zbigniew Walczak

Recently, the authors [arXiv quant-ph 1209.3706] studied quantum discord for Werner mixed states based on the four entangled coherent states, which are used for quantum teleportation of single qubit information encoded in superposed…

Quantum Physics · Physics 2012-10-09 Ajay K Maurya , Manoj K Mishra , Hari Prakash

We analyse the generation of quantum discord by means of the dynamical Casimir effect in superconducting waveguides modulated by superconducting quantum interferometric devices. We show that for realistic experimental parameters, the…

Quantum Physics · Physics 2015-07-17 Carlos Sabín , Ivette Fuentes , Göran Johansson

Information is encoded in a qubit in the form of its Bloch vector. In this paper, we propose protocols for remote transfers of information in a known and an unknown qubit to qudits using $SU(2)$- invariant $\frac{1}{2}\otimes S$ discordant…

Quantum Physics · Physics 2021-12-16 Sooryansh Asthana , Rajni Bala , V. Ravishankar

It is shown that a choice of degrees of freedom of a bipartite continuous variable system determines amount of non-classical correlations (quantified by discord) in the system's state. Non-classical correlations (that include entanglement…

Quantum Physics · Physics 2013-04-01 M. Dugic , M. Arsenijevic , J. Jeknic-Dugic

There has been an increasing interest in exploring quantities associated with quantum information at colliders. We perform a detailed analysis describing how to measure the quantum discord in the top anti-top quantum state at the Large…

High Energy Physics - Phenomenology · Physics 2025-03-05 Tao Han , Matthew Low , Navin McGinnis , Shufang Su

We study the pairwise quantum discord (QD) for a symmetric multi-qubit system in different types of noisy channels, such as phase-flip, amplitude damping, phase-damping, and depolarizing channels. Using the QD and geometric measure of…

Quantum Physics · Physics 2016-02-17 You-neng Guo , Mao-fa Fang , Zeng Ke , Guo-you Wang

Among various definitions of quantum correlations, quantum discord has attracted considerable attention. To find analytical expression of quantum discord is an intractable task. Exact results are known only for very special states, namely,…

Quantum Physics · Physics 2015-05-27 Mingjun Shi , Fengjian Jiang , Chunxiao Sun , Jiangfeng Du

The role of SU(2) invariants for the classification of multiparty entanglement is discussed and exemplified for the Kempe invariant I_5 of pure three-qubit states. It is found to being an independent invariant only in presence of both…

Quantum Physics · Physics 2010-03-30 A. Osterloh

Quantum discord measures quantum correlation by comparing the quantum mutual information with the maximal amount of mutual information accessible to a quantum measurement. This paper analyzes the properties of diagonal discord, a simplified…

Quantum Physics · Physics 2019-03-04 Zi-Wen Liu , Ryuji Takagi , Seth Lloyd

The symmetric subspace of multi-qubit systems, that is, the space of states invariant under permutations, is commonly encountered in applications in the context of quantum information and communication theory. It is known that the symmetric…

Quantum Physics · Physics 2026-03-12 Angel Ballesteros , Ivan Gutierrez-Sagredo , Jose de Ramon , J. Javier Relancio

In this brief review, we discuss the role that quantum correlations, as quantified by quantum discord, play in two interesting settings. The first one is discerning which unitaries have been applied on a quantum system, by taking advantage…

Quantum Physics · Physics 2017-08-01 Mile Gu , Stefano Pirandola

A modified definition of quantum mechanical uncertainty D for spin systems, which is invariant under the action of SU(2), is suggested. Its range is shown to be h^2j<D<h^2j(j+1) within any irreducible representation j of SU(2) and its mean…

Quantum Physics · Physics 2007-05-23 Nuno Barros e Sa

We review concepts and methods associated with quantum discord and related topics. We also describe their possible connections with other aspects of quantum information and beyond, including quantum communication, quantum computation,…

Quantum Physics · Physics 2018-01-17 Anindita Bera , Tamoghna Das , Debasis Sadhukhan , Sudipto Singha Roy , Aditi Sen De , Ujjwal Sen

This paper examines the coherence in multipartite systems. We first discuss the distribution of total coherence in a given multipartite quantum state into discord between subsystems and coherent dissonance in each individual subsystem,…

Quantum Physics · Physics 2018-09-26 Zhengjun Xi

Originally introduced as the difference between two possible forms of quantum mutual information, quantum discord has posteriorly been shown to admit a formulation according to which it measures a distance between the state under scrutiny…

Quantum Physics · Physics 2018-10-01 P. R. Dieguez , R. M. Angelo

Classical correlations of ground states typically decay exponentially and polynomially, respectively for gapped and gapless short-ranged quantum spin systems. In such systems, entanglement decays exponentially even at the quantum critical…

Quantum Physics · Physics 2016-01-27 Debasis Sadhukhan , Sudipto Singha Roy , Debraj Rakshit , R. Prabhu , Aditi Sen De , Ujjwal Sen

We consider quantum correlations in a spin-1/2 open chain of $N$ nodes with the XY Hamiltonian using different bases for the density matrix representation and the initial state with a single polarized node. These bases of our choice are…

Quantum Physics · Physics 2015-06-05 E. B. Fel'dman , A. I. Zenchuk

The approach to extend the notion of entanglement for characterizing the properties of quantum correlations in the state of a single qudit is presented. New information and entropic inequalities, such as the subadditivity condition, strong…

Quantum Physics · Physics 2014-09-16 Margarita A. Man'ko , Vladimir I. Man'ko