Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Structural instability of two- and three-dimensional pyrochlore spin
  lattices in high magnetic fields   We consider the quantum spin-$s$ $XXZ$ Heisenberg antiferromagnet on the two-
and three-dimensional pyrochlore lattices and examine a spin-Peierls mechanism
of lowering the total energy by a lattice distortion in a high magnetic field.
For the exact eigenstates consisting of several independent localized magnons
in a ferromagnetic environment we show the existence of a spin-Peierls
instability by rigorous analytical calculations. In addition we report on exact
diagonalization data for finite two-dimensional pyrochlore lattices up to N=64
sites. We discuss a scenario of the field-tuned changes in the ground-state
properties of the frustrated spin lattices due to the coupling between spin and
lattice degrees of freedom.

34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio