Quantum discord in a~three-spin system in an~external magnetic field
Teoretičeskaâ i matematičeskaâ fizika, Tome 181 (2014) no. 2, pp. 387-400
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We study quantum correlations in a bipartite heteronuclear $2{\times}1$ system with three spins $S=1/2$ in an external magnetic field at high and low temperatures. We analytically determine the minimum of the system conditional entropy at high temperatures after measurements on the one-spin subsystem for any relations between the spin frequencies of both subsystems. As a result, we obtain analytic expressions for the measure of quantum correlations, i.e., for the quantum discord in three-qubit systems, for the first time in the high-temperature case. We obtain the minimum of the low-temperature conditional entropy numerically. We investigate the quantum discord evolution and the relation between the classical and quantum correlations.
Keywords:
quantum correlation, quantum discord, quantum conditional entropy, mutual information, reduced density matrix.
@article{TMF_2014_181_2_a10,
author = {S. I. Doronin and E. I. Kuznetsova and \'E. B. Fel'dman},
title = {Quantum discord in a~three-spin system in an~external magnetic field},
journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
pages = {387--400},
publisher = {mathdoc},
volume = {181},
number = {2},
year = {2014},
language = {ru},
url = {http://geodesic.mathdoc.fr/item/TMF_2014_181_2_a10/}
}
TY - JOUR AU - S. I. Doronin AU - E. I. Kuznetsova AU - É. B. Fel'dman TI - Quantum discord in a~three-spin system in an~external magnetic field JO - Teoretičeskaâ i matematičeskaâ fizika PY - 2014 SP - 387 EP - 400 VL - 181 IS - 2 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/TMF_2014_181_2_a10/ LA - ru ID - TMF_2014_181_2_a10 ER -
%0 Journal Article %A S. I. Doronin %A E. I. Kuznetsova %A É. B. Fel'dman %T Quantum discord in a~three-spin system in an~external magnetic field %J Teoretičeskaâ i matematičeskaâ fizika %D 2014 %P 387-400 %V 181 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/item/TMF_2014_181_2_a10/ %G ru %F TMF_2014_181_2_a10
S. I. Doronin; E. I. Kuznetsova; É. B. Fel'dman. Quantum discord in a~three-spin system in an~external magnetic field. Teoretičeskaâ i matematičeskaâ fizika, Tome 181 (2014) no. 2, pp. 387-400. http://geodesic.mathdoc.fr/item/TMF_2014_181_2_a10/