Geometric measure of quantum discord for entanglement of Dirac fields in noninertial frames

We extend the geometric measure of quantum discord, introduced and computed for two-qubit states, to quantify non-classical correlations in composite Gaussian states of continuous variable systems. We lay the formalism for the evaluation of a Gaussian geometric discord in two-mode Gaussian states, and present explicit formulas for the class of two-mode squeezed thermal states. In such a case, under physical constraints of bounded mean energy, geometric discord is shown to admit upper and lower bounds for a fixed value of the conventional (entropic) quantum discord. We finally discuss alternative geometric approaches to quantify Gaussian quadrature correlations.

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Pairwise correlations via quantum discord and its geometric measure in a four-qubit spin chain

Journal of the Egyptian Mathematical Society ◽

10.1016/j.joems.2012.10.005 ◽

2013 ◽

Vol 21 (1) ◽

pp. 68-74 ◽

Cited By ~ 9

Author(s):

Abdel-Baset A. Mohamed

Keyword(s):

Spin Chain ◽

Quantum Discord ◽

Geometric Measure ◽

Pairwise Correlations

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Tight lower bound to the geometric measure of quantum discord

Physical Review A ◽

10.1103/physreva.85.024302 ◽

2012 ◽

Vol 85 (2) ◽

Cited By ~ 55

Author(s):

Ali Saif M. Hassan ◽

Behzad Lari ◽

Pramod S. Joag

Keyword(s):

Lower Bound ◽

Quantum Discord ◽

Geometric Measure

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QUANTUM CORRELATIONS IN THE "q-DEFORMED" WERNER STATE

International Journal of Quantum Information ◽

10.1142/s0219749913500184 ◽

2013 ◽

Vol 11 (02) ◽

pp. 1350018 ◽

Cited By ~ 2

Author(s):

BO LIU ◽

KANG XUE ◽

GANGCHENG WANG ◽

CHUNFANG SUN ◽

LIDAN GOU ◽

...

Keyword(s):

Quantum Discord ◽

Singlet State ◽

Great Influence ◽

Quantum Correlations ◽

Werner State ◽

Single Loop ◽

Geometric Measure ◽

Topological Parameter ◽

Spin Singlet ◽

Two Parameters

We investigate quantum discord of the "q-deformed" Werner state via Yang–Baxterization approach. There are two parameters q and u in this "q-deformed" Werner state. The parameter u, which plays an important role in some typical models, is related to the probability of the "q-deformed" two-qubit spin singlet state in this study. The "q-deformed" parameter q is related to the single loop through d = q + q-1. When topological parameter d approaches 2 (i.e. q → 1), the "q-deformed" Werner state degenerates into the well-known Werner state. The results show that topological parameter d has great influence on quantum correlations of the "q-deformed" Werner state. When we fix the parameter u, the quantum correlations decrease with increasing the single loop d. When d approaches +∞ (i.e. q → 0+ or +∞), quantum discord, geometric measure of quantum discord and entanglement all tend to 0. While d approaches 2 (i.e. q → 1), all of them just have the same results with the Werner state.

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