Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Multireference configuration interaction and perturbation theory without
  reduced density matrices   The computationally expensive evaluation and storage of high-rank reduced
density matrices (RDMs) has been the bottleneck in the calculation of dynamic
correlation for multireference wave functions in large active spaces. We
present a stochastic formulation of multireference configuration interaction
(MRCI) and perturbation theory (MRPT) that avoids the need for these expensive
RDMs. The algorithm presented here is flexible enough to incorporate a wide
variety of active space reference wave functions, including selected
configuration interaction, matrix product states, and symmetry-projected
Jastrow mean field wave functions. It enjoys the usual attractive features of
Monte Carlo methods, such as embarrassing parallelizability and low memory
costs. We find that the stochastic algorithm is already competitive with the
deterministic algorithm for small active spaces, containing as few as 14
orbitals. We illustrate the utility of our stochastic formulation using
benchmark applications.

29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
25
The categories of this paper are: patt-sol
21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys