Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Preconditioning and perturbative estimators in full configuration
  interaction quantum Monte Carlo   We propose the use of preconditioning in FCIQMC which, in combination with
perturbative estimators, greatly increases the efficiency of the algorithm. The
use of preconditioning allows a time step close to unity to be used (without
time-step errors), provided that multiple spawning attempts are made per
walker. We show that this approach substantially reduces statistical noise on
perturbative corrections to initiator error, which improve the accuracy of
FCIQMC but which can suffer from significant noise in the original scheme.
Therefore, the use of preconditioning and perturbatively-corrected estimators
in combination leads to a significantly more efficient algorithm. In addition,
a simpler approach to sampling variational and perturbative estimators in
FCIQMC is presented, which also allows the variance of the energy to be
calculated. These developments are investigated and applied to benzene
(30e,108o), an example where accurate treatment is not possible with the
original method.

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The categories of this paper are: cs
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph