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A generalization of the geometric measure of quantum discord is introduced in this article, based on Hellinger distance. Our definition has virtues of computability and independence of local measurement. In addition it also does not suffer…

Quantum Physics · Physics 2016-02-02 Hai-Tao Cui , Jun-Long Tian , Gui Yang

The original definition of quantum discord of bipartite states was defined over one-sided projective measurements, it describes quantum correlation more extensively than entanglement. Dakic, Vedral, and Brukner [Phys. Rev. Lett. 105 (2010)…

Quantum Physics · Physics 2015-05-27 Jianwei Xu

The concept of quantum discord aims at unveiling quantum correlations that go beyond those described by entanglement. Its original formulation [J. Phys. A 34, 6899 (2001); Phys. Rev. Lett 88, 017901 (2002)] is difficult to compute even for…

We present a reliable algorithm to evaluate quantum discord for general two--qubit states, amending and extending an approach recently put forward for the subclass of X--states. A closed expression for the discord of arbitrary states of two…

Quantum Physics · Physics 2011-05-23 Davide Girolami , Gerardo Adesso

The dynamics of a geometric measure of the quantum discord (GMQD) under decoherence is investigated. We show that the GMQD of a two-qubit state can be alternatively obtained through the singular values of a $3\times4$ matrix whose elements…

Quantum Physics · Physics 2010-09-07 Xiao-Ming Lu , Zheng-Jun Xi , Zhe Sun , Xiaoguang Wang

We investigate and compare three distinguished geometric measures of bipartite quantum correlations that have been recently introduced in the literature: the geometric discord, the measurement-induced geometric discord, and the discord of…

Quantum Physics · Physics 2016-05-26 Wojciech Roga , Dominique Spehner , Fabrizio Illuminati

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

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 standard method of "measuring" quantum wavefunction is the technique of {\it indirect} quantum state tomography. Owing to conceptual novelty and possible advantages, an alternative {\it direct} scheme was proposed and demonstrated…

Quantum Physics · Physics 2023-09-26 Lupei Qin , Luting Xu , Wei Feng , Xin-Qi Li

The minimal Bures distance of a quantum state of a bipartite system AB to the set of classical states for subsystem A defines a geometric measure of quantum discord. When A is a qubit, we show that this geometric quantum discord is given in…

Quantum Physics · Physics 2013-12-24 Dominique Spehner , Miguel Orszag

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

Radhakrishnan et.al [Phys. Rev. Lett. 124, 110401 (2020)] proposed a generalization of quantum discord to multipartite systems, which is consistency with the conventional definition of discord in bipartite systems and derived explicit…

Quantum Physics · Physics 2024-07-26 Ali Saif M. Hassan , Pramod S. Joag

We investigate the geometric picture of the level surfaces of quantum entanglement and geometric measure of quantum discord (GMQD) of a class of X-states, respectively. This pictorial approach provides us a direct understanding of the…

Quantum Physics · Physics 2013-12-03 Wei Song , Long-Bao Yu , Ping Dong , Da-Chuang Li , Ming Yang , Zhuo-Liang Cao

We present an effective measurement scheme for the solid-state qubits that does {\bf not} introduce extra decoherence to the qubits until the measurement is switched on by a resonant pulse. The resonant pulse then maximally entangles the…

Quantum Physics · Physics 2011-07-26 L. Tian , S. Lloyd , T. P. Orlando

We present the complete solution of the problem of determination of trace-norm geometric discord for arbitrary two-qubit state. Final answer is achieved due to effective reduction of the problem to the study of critical points of certain…

Quantum Physics · Physics 2019-06-12 Piotr Lugiewicz , Andrzej Frydryszak , Lech Jakobczyk

We extend the geometric measure of quantum discord, introduced and computed for two-qubit states in [B. Dakic, C. Brukner, and V. Vedral, Phys. Rev. Lett. 105, 190502 (2010)], to quantify non-classical correlations in composite Gaussian…

Quantum Physics · Physics 2011-12-13 Gerardo Adesso , Davide Girolami

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 scheme to measure the quantum state of photons in a cavity. The proposal is based on the concept of quantum weak values and applies equally well to both the solid-state circuit and atomic cavity quantum electrodynamics (QED)…

Quantum Physics · Physics 2019-04-24 Lupei Qin , Zhong Wang , Cheng Zhang , Xin-Qi Li

We describe an efficient DQC1-algorithm to quantify the amount of Geometric Quantum Discord present in the output state of a DQC1 computation. DQC1 is a model of computation that utilizes separable states to solve a problem with no known…

Quantum Physics · Physics 2012-07-13 G. Passante , O. Moussa , R. Laflamme

We define a new measure of quantum correlations in bipartite quantum systems given by the Bures distance of the system state to the set of classical states with respect to one subsystem, that is, to the states with zero quantum discord. Our…

Quantum Physics · Physics 2013-12-23 Dominique Spehner , Miguel Orszag
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