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This work is at the interface of graph theory and quantum mechanics. Quantum correlations epitomize the usefulness of quantum mechanics. Quantum discord is an interesting facet of bipartite quantum correlations. Earlier, it was shown that…

Quantum Physics · Physics 2019-04-08 Supriyo Dutta , Bibhas Adhikari , Subhashish Banerjee

We study the computational complexity of quantum discord (a measure of quantum correlation beyond entanglement), and prove that computing quantum discord is NP-complete. Therefore, quantum discord is computationally intractable: the running…

Quantum Physics · Physics 2014-03-31 Yichen Huang

We investigate quantum states that posses both maximum entanglement and maximum discord between the pertinent parties. Since entanglement (discord) is defined only for bipartite (two qubit) systems, we shall introduce an appropriate sum…

Quantum Physics · Physics 2013-03-27 J. Batle , M. Casas , A. Plastino

The quantumness of the correlation known as quantum correlation is usually measured by quantum discord. So far various quantum discords can be roughly understood as indirect measure by some special discrepancy of two quantities. We present…

Quantum Physics · Physics 2015-06-16 Chang-shui Yu , Heng Fan

We propose a new criterion to judge zero quantum discord for arbitrary bipartite states. A bipartite quantum state has zero quantum discord if and only if all blocks of its density matrix are normal matrices and commute with each other.…

Quantum Physics · Physics 2015-03-19 Jie-Hui Huang , Lei Wang , Shi-Yao Zhu

We investigate the dynamics of quantum discord and entanglement for a class of mixed qubit-qutrit states assuming that only the qutrit is under the action of a dephasing channel. We demonstrate that even though the entanglement in the…

Quantum Physics · Physics 2013-04-02 G. Karpat , Z. Gedik

In this paper we present a measure of quantum correlation for a multipartite system, defined as the sum of the correlations for all possible partitions. Our measure can be defined for quantum discord (QD), geometric quantum discord (GQD),…

Quantum Physics · Physics 2013-04-18 Zhi-Hao Ma , Zhi-Hua Chen , Felipe F. Fanchini

We investigate collective radiant properties of two separated atoms in X-type quantum states. We show that quantum correlations measured by quantum discord (QD) can induce and enhance superradiance and subradiance in the two-atom system…

Quantum Physics · Physics 2013-12-04 Shi-Qing Tang , Ji-Bing Yuan , Xin-Wen Wang , Le-Man Kuang

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 quantize prisoners dilemma and chicken game by our generalized quantization scheme to explore the role of quantum discord in quantum games. In order to establish this connection we use Werner-like state as an initial state of the game.…

Quantum Physics · Physics 2015-03-17 Ahmad Nawaz , A. H. Toor

Among various definitions of quantum correlations, quantum discord has attracted considerable attention. To find analytical expression of quantum discord is an intractable task. In this paper, we discuss thoroughly the case of two-qubit…

Quantum Physics · Physics 2015-05-28 Mingjun Shi , Wei Yang , Fengjian Jiang , Jiangfeng Du

The dynamics of the quantum discord for two identical qubits in both two independent single-mode cavities and a common single-mode cavity are discussed. For the initial Bell state with correlated spins, while the entanglement sudden death…

Quantum Physics · Physics 2015-06-04 Chen Wang , Qing-Hu Chen

We report a study on the zero-temperature quantum discord as a measure of two-spin correlation of a transverse XY spin chain following a quench across a quantum critical point and investigate the behavior of mutual information, classical…

Statistical Mechanics · Physics 2021-02-15 Tanay Nag , Ayoti Patra , Amit Dutta

Two classically identical expressions for the mutual information generally differ when the two systems involved are quantum. We investigate this difference -- quantum discord -- and show that it can be used as a criterion for the…

Quantum Physics · Physics 2013-05-29 Harold Ollivier , Wojciech H. Zurek

We show that two qubits, initially in a fully classical state, can develop significant quantum correlations as measured by the quantum discord (QD) under the action of a local memoryless noise (specifically we consider the case of a…

Quantum Physics · Physics 2012-02-10 Francesco Ciccarello , Vittorio Giovannetti

Two-qubit X-state is a large class of quantum states which plays an important role in the quantification and dynamical study of quantum correlations. However, the corresponding quantification of quantum discord is still missing for bona…

Quantum Physics · Physics 2021-06-23 Chunhe Xiong , Guijun Zhang

We study and compare the time evolutions of concurrence and quantum discord in a driven system of two interacting qubits prepared in a generic Werner state. The~corresponding quantum dynamics is exactly treated and manifests the appearance…

Quantum Physics · Physics 2020-10-09 Iulia Ghiu , Roberto Grimaudo , Tatiana Mihaescu , Aurelian Isar , Antonino Messina

The study of quantum correlations in High-dimensional bipartite systems is crucial for the development of quantum computing. We propose relative entropy as a distance measure of correlations may be measured by means of the distance from the…

Quantum Physics · Physics 2016-04-12 M. Mahdian , M. B. Arjmandi

In this paper, by exploiting the weak measurement and quantum measurement re- versal (WMQMR) procedure, we propose a scheme to show how one can protect the geometric quantum discord (GQD) of a two-qutrit V-type atomic system each of which…

Quantum Physics · Physics 2017-02-01 N. Behzadi , E. Faizi , O. Heibati

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