Temperature dependence of the NMR relaxation rate 1 /T_{1} for quantum spin chains
Abstract
We present results of numerical simulations performed on onedimensional spin chains in order to extract the socalled relaxation rate 1 /T_{1} accessible through NMR experiments. Building on numerical tensor network methods using the matrix product states formalism, we can follow the nontrivial crossover occurring in critical chains between the hightemperature diffusive classical regime and the lowtemperature response described by the TomonagaLuttinger liquid (TLL) theory, for which analytical expressions are known. In order to compare analytics and numerics, we focus on a generic spin1 /2 X X Z chain which is a paradigm of gapless TLL, as well as a more realistic spin1 anisotropic chain, modeling the DTN material, which can be either in a trivial gapped phase or in a TLL regime induced by an external magnetic field. Thus, by monitoring the finite temperature crossover, we provide quantitative limits on the range of validity of TLL theory, that will be useful when interpreting experiments on quasionedimensional materials.
 Publication:

Physical Review B
 Pub Date:
 October 2016
 DOI:
 10.1103/PhysRevB.94.144409
 arXiv:
 arXiv:1606.09502
 Bibcode:
 2016PhRvB..94n4409D
 Keywords:

 Condensed Matter  Strongly Correlated Electrons
 EPrint:
 12 pages, 6 figures