Quantum correlations in a system of nuclear s=1/2 spins in a strong magnetic field

Abstract

Entanglement and quantum discord for a pair of nuclear spins $s=1/2$ in a nanopore filled with a gas of spin-carrying molecules (atoms) are studied. The correlation functions describing dynamics of dipolar coupled spins in a nanopore are found. The dependence of spin-pair entanglement on the temperature and the number of spins is obtained from the reduced density matrix, which is centrosymmetric (CS). An analytic expression for the concurrence is obtained for an arbitrary CS density matrix. It is shown that the quantum discord as a measure of quantum correlations attains a significant value at low temperatures. It is shown also that the discord in the considered model has "flickering" character and disappears periodically in the course of the time evolution of the system. The geometric discord is studied for arbitrary $4\times 4$ CS density matrices.

14 pages, 3 figures

References in corpus (3)

• Quantum discord and the power of one qubit
• Necessary and sufficient condition for non-zero quantum discord
• Experimental quantum computing without entanglement

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• NMR dynamics of quantum discord for spin-carrying gas molecules in a closed nanopore
• Calculation of quantum discord and entanglement measures using the random mutations optimization algorithm
• Influence of environment on quantum correlations in two-spin systems with dipole-dipole interactions