Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Simulated nuclear spin-lattice relaxation in Heisenberg ferrimagnets:
  Indirect observation of quadratic dispersion relations   In response to recent proton spin relaxation-time measurements on
NiCu(pba)(H$_2$O)$_3$$\cdot$2H$_2$O with ${pba}=1,3{-propylenebis(oxamato)}$,
which is an excellent one-dimensional ferrimagnetic Heisenberg model system of
spin-$(1,{1/2})$, we study the Raman relaxation process in spin-$(S,s)$ quantum
ferrimagnets on the assumption of predominantly dipolar hyperfine interactions
between protons and magnetic ions. The relaxation time $T_1$ is formulated
within the spin-wave theory and is estimated as a function of temperature and
an applied field $H$ by a quantum Monte Carlo method. The low-temperature
behavior of the relaxation rate $T_1^{-1}$ qualitatively varies with $(S,s)$,
while $T_1^{-1}$ is almost proportional to $H^{-1/2}$ due to the characteristic
dispersion relations.

10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin