Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Density Matrix Renormalisation Group Variants for Spin Systems   This thesis gives an extension for the Density Matrix Renormalisation Group
(DMRG) to two dimensions and described a newly developed combination of the
DMRG and a Green Function Monte Carlo simulation (GFMC).
  The first two chapters focus on the DMRG method. The properties are reviewed
and it is shown that good quality results can be obtained for two-dimensional
systems through finite-size scaling.
  In the third and fourth chapter the properties of the two-dimensional
frustrated Heisenberg model are analysed using a similar combination of DMRG
and finite-size scaling.
  The final chapter presents the combination of the DMRG and GFMC with
Stochastic Reconfiguration (Sorella, Capriotti cond-mat/9902211) We find an
intermediate phase between Neel and collinear long-range order. This phase
shows spatial inhomogeneities with a tendency towards plaquette formation.

14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
7
The categories of this paper are: hep-th