In this work, quantum correlations in two model systems which can be invesitgated by means of solid-state NMR are considered. The first is a two-spin system in NMR spin-locking experiment, where two schemes of spin-locking are considered. Concurrence is calculated for both schemes assuming the initial thermodynamic equilibrium state. Quantum discord is calculated analytically in the high-temperature approximation. The second model system is the spin-1/2 chain with the XY interaction, where the transfer of multiple quantum (MQ) coherences from one end of the chain to another is studied. The conditions under which the density matrix of the receiver is a block-scaled version of the sender’s density matrix are found.
Quantum entanglement is a measure of quantum correlations which are responsible for effective work of quantum devices (in particular, quantum computers), significantly outperforming their classical counterparts.1 Here, we investigate quantum entanglement in the trimer clusters consisting of three electron spins sited in vertexes of an isosceles triangle. We consider entanglement of two subsystems of the system. The first subsystem consists of spins sited on the triangle baseline and the second subsystem consists of a spin equidistant from others. We generalized the Bleany-Bowers equation2, 3 for trimer clusters. It is shown that entanglement can emerge only in the case of the antiferromagnetic interaction of the subsystems. An equation for the temperature of the entanglement emergence is derived. The criterion of the double negativity4 is used in order to find the dependence of the entanglement on the temperature.
KEYWORDS: Calcium, Process modeling, Quantum information, Systems modeling, Fluorine, Magnetism, Quantum information processing, Lab on a chip, Polarization, Free electron lasers
Multiple quantum (MQ) NMR methods1 are applied to the analysis of various problems of quantum information processing. It is shown that the two-spin/two-quantum Hamiltonian1 describing MQ NMR dynamics is related to the flip-flop Hamiltonian of a one-dimensional spin system in the approximation of the nearest neighbor interactions. As a result, it is possible to organize quantum state transfer along a linear chain. MQ NMR experiments are performed on quasi-one-dimensional chains of 19F nuclei in calcium fluorapatite Ca5(PO4)3F. Relaxation of the MQ NMR coherences is considered as the simplest model of decoherence processes. A theory of the dipolar relaxation of the MQ NMR coherences in one-dimensional systems is developed. A good agreement of the theoretical predictions and the experimental data is obtained.
Conference Committee Involvement (1)
The International Conference on Micro- and Nano-Electronics 2018
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