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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

Quantum discord provides a measure for quantifying quantum correlations beyond entanglement and is very hard to compute even for two-qubit states because of the minimization over all possible measurements. Recently a simple algorithm to…

Quantum Physics · Physics 2011-10-10 Qing Chen , Chengjie Zhang , Sixia Yu , X. X. Yi , C. H. Oh

We analyze a system consisting of an oscillator coupled to a field. With the field traced out as an environment, the oscillator loses coherence on a very short {\it decoherence timescale}; but, on a much longer {\it relaxation timescale},…

General Relativity and Quantum Cosmology · Physics 2011-08-04 J. R. Anglin , R. Laflamme , W. H. Zurek , J. P. Paz

Quantum discord is a measure based on local projective measurements which captures quantum correlations that may not be fully captured by entanglement. A change in the measurement process, achieved by replacing rank-one projectors with a…

Quantum Physics · Physics 2020-08-17 Akanksha Gautam , Varad R. Pande , Amandeep Singh , Kavita Dorai , Arvind

Coherence is the most fundamental quantum feature in quantum mechanics. For a bipartite quantum state, if a measurement is performed on one party, the other party, based on the measurement outcomes, will collapse to a corresponding state…

Quantum Physics · Physics 2017-03-09 Jun Zhang , Si-ren Yang , Yang Zhang , Chang-shui Yu

The possibility of consistency between the basic quantum principles of quantum mechanics and wave function collapse is reexamined. A specific interpretation of environment is proposed for this aim and applied to decoherence. When the…

Quantum Physics · Physics 2015-05-28 Roland Omnès

Quantum coherence is a key resource in quantum information processing scenarios, and quantifying coherence is an important task for both quantum foundation and quantum technology. However, until now, all most of coherence measures are…

Quantum Physics · Physics 2017-10-24 Wei-Chen Wang , Mao-Fa Fang , Min Yu

Within the unified framework of exploiting the relative entropy as a distance measure of quantum correlations, we make explicit the hierarchical structure of quantum coherence, quantum discord and quantum entanglement in multipartite…

Quantum Physics · Physics 2015-08-19 Yao Yao , Xing Xiao , Li Ge , C. P. Sun

When quantum information is spread over a system through nonclassical correlation, it makes retrieving information by local measurements difficult---making global measurement necessary for optimal parameter estimation. In this paper, we…

Quantum Physics · Physics 2018-07-13 Akira Sone , Quntao Zhuang , Paola Cappellaro

Quantum coherence is the most fundamental feature of quantum mechanics. The usual understanding of it depends on the choice of the basis, that is, the coherence of the same quantum state is different within different reference framework. To…

Quantum Physics · Physics 2017-04-17 Chang-shui Yu , Yi-ren Yang , Bao-qing Guo

This work deals with two pressing issues in the design and operation of Josephson qubits -- loss of coherence and measurement. (Longer abstract follows in the work.)

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Kristian Rabenstein

The second order quantum decoherence (SOQDC)is proposed as a novel description for the loss of quantum coherence only reflected by second order quantum correlations. By calculating the two-time correlation function, the phenomenon of SOQDC…

Quantum Physics · Physics 2007-05-23 D. L. Zhou , C. P. Sun

Quantum discord is a measure of non-classical correlations, which are excess correlations inherent in quantum states that cannot be accessed by classical measurements. For multipartite states, the classically accessible correlations can be…

Quantum Physics · Physics 2019-09-18 Mark Bradshaw , Ping Koy Lam , Syed M. Assad

It is shown that if the wave function of a quantum system undergoes an arbitrary random transformation such that the diagonal elements of the density matrix in the decoherence basis associated with a preferred observable remain constant,…

Quantum Physics · Physics 2025-04-24 Dorje C. Brody , Lane P. Hughston

Geometric quantum discord is a well-defined measure of quantum correlation if Schatten 1-norm (trace norm) is adopted as a distance measure. Here, we analytically investigate the dynamical behavior of the 1-norm geometric quantum discord…

Quantum Physics · Physics 2013-05-08 J. D. Montealegre , F. M. Paula , A. Saguia , M. S. Sarandy

A multi-slit interference experiment, with which-way detectors, in the presence of environment induced decoherence, is theoretically analyzed. The effect of environment is modeled via a coupling to a bath of harmonic oscillators. Through an…

Quantum Physics · Physics 2018-11-02 Anu Venugopalan , Sandeep Mishra , Tabish Qureshi

The inherent connection between noise and disturbance is one of the most fundamental features of quantum measurements. In the two well-known extreme cases a measurement either makes no disturbance but then has to be totally noisy or is as…

Quantum Physics · Physics 2014-01-08 Teiko Heinosaari , Takayuki Miyadera

Quantum noise is ubiquitous to quantum systems as they incessantly interact with their surroundings and results in degrading useful resources such as coherence for single quantum systems and quantum correlations for multipartite systems.…

Quantum Physics · Physics 2016-11-30 Kaifeng Bu , Swati , Uttam Singh , Junde Wu

The effect of measurement attributes (quantum level of precision, finite duration) on the classical and quantum correlations is analysed for a pair of qubits immersed in a common reservoir. We show that the quantum discord is enhanced as…

Quantum Physics · Physics 2014-11-21 A. Thilagam

A general state of an $m\otimes n$ system is a classical-quantum state if and only if its associated $A$-correlation matrix (a matrix constructed from the coherence vector of the party $A$, the correlation matrix of the state, and a…

Quantum Physics · Physics 2016-04-19 S. Javad Akhtarshenas , Hamidreza Mohammadi , Saman Karimi , Zahra Azmi