38 research outputs found
Transfer of 0-order coherence matrix along spin-1/2 chain
In this work, we study transfer of coherence matrices along spin-1/2 chains
of various length. Unlike higher order coherence matrices, 0-order coherence
matrix can be perfectly transferred if its elements are properly fixed. In
certain cases, to provide the perfect transfer, an extended receiver together
with optimized its unitary transformation has to be included into the protocol.
In this work, the asymptotic perfectly transferable 0-order coherence matrix
for an infinitely long chain is considered and deviation of a perfectly
transferred state from this asymptotic state is studied as a function of the
chain length for various sizes of the extended receiver. The problem of
arbitrary parameter transfer via the nondiagonal elements of the 0-order
coherence matrix is also considered and optimized using the unitary
transformation of the extended receiver.Comment: 32 pages, 5 figure
Dipolar relaxation of multiple-quantum NMR coherences in a linear homogeneous chain of 19F nuclei in calcium fluoroapatite
Experimental and theoretical investigations of dynamics and relaxation of multiple quantum (MQ) nuclear magnetic resonance (NMR) coherences of the zeroth and second orders are performed in a quasi-one-dimensional chain of nuclear spins of 19F in calcium fluorapatite. MQ NMR dynamics are studied on the preparation period of the MQ NMR experiment in the approximation of nearest neighbor interactions. The density matrix of the system at the end of the preparation period is used as the initial condition for the study of the relaxation process on the evolution period of the MQ NMR experiment. The relaxation asymptotics of the intensity of the MQ NMR coherence of the zeroth order is obtained. Relaxation of the MQ NMR coherence of the second order is investigated with ZZ part of the dipole-dipole interactions. The experimental data qualitatively agree with the results of the developed theory