Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A favorably-scaling natural-orbital functional theory based on
  higher-order occupation probabilities   We introduce a novel energy functional for ground-state electronic-structure
calculations. Its fundamental variables are the natural spin-orbitals of the
implied singlet many-body wave function and their joint occupation
probabilities. The functional derives from a sequence of controlled
approximations to the two-particle density matrix. Algebraic scaling of
computational cost with electron number is obtainable in general, and
Hartree-Fock scaling in the seniority-zero version of the theory. Results
obtained with the latter version for saturated small molecular systems are
compared with those of highly-accurate quantum-chemical computations. The
numerical results are variational, capturing most of the correlation energy
from equilibrium to dissociation. Their accuracy is considerably greater than
that obtainable with current density-functional theory approximations and with
current functionals of the one-particle density matrix only.

16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con