Multiple-Quantum NMR Spectroscopy and Quantum Information Spreading Control in the Spin Systems of Solids.

Zobov, V. E.; Lundin, A. A.

Multiple-quantum (MQ) solid-state NMR spectroscopy allows the growth of multiple-spin correlations and, thus, the spreading of quantum information in the object under study to be observed. Recently, in [11] it was proposed to control this process through a controlled perturbation added to the effective Hamiltonian that causes degradation of correlated spin clusters with a rate determined by the number of spins K in a cluster. However, this perturbation can also lead to degradation whose rate is determined by the coherence order M. In this paper, to investigate the influence of a small added perturbation, we used an expansion into orthogonal operators that allowed the cluster size distribution to be taken into account. In our calculations we realized a simple model with known amplitudes of the expansion into a complete set of orthogonal operators in the absence of a perturbation. We performed numerical calculations of the "preparation time" dependences of the MQ spectra, their second moments, and the coherence orders at which the MQ spectra decrease by a factor of e as well as the average correlated spin cluster sizes . The coherence-order-dependent contribution to the degradation is shown to change the shape of the MQ spectrum. In particular, as the preparation time increases, the MQ spectrum can be stabilized, while the growth of is retained. Due to the change in the shape of the MQ spectrum, the relations of its characteristics to the number change compared to those for the Gaussian function (traditionally used to process the experiments). These changes should be taken into account when studying the spreading of quantum information through MQ spectroscopy.

INFORMATION resources management; ORTHOGONALIZATION; GAUSSIAN function; NUMERICAL calculations; NUCLEAR magnetic resonance spectroscopy; SPECTROMETRY

Journal of Experimental & Theoretical Physics, 2022, Vol 135, Issue 5, p752

1063-7761

Academic Journal

10.1134/S1063776122110139