Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The second-order reduced density matrix method and the two-dimensional
  Hubbard model   The second-order reduced density matrix method (the RDM method) has performed
well in determining energies and properties of atomic and molecular systems,
achieving coupled-cluster singles and doubles with perturbative triples (CC
SD(T)) accuracy without using the wave-function. One question that arises is
how well does the RDM method perform with the same conditions that result in
CCSD(T) accuracy in the strong correlation limit. The simplest and a
theoretically important model for strongly correlated electronic systems is the
Hubbard model. In this paper, we establish the utility of the RDM method when
employing the $P$, $Q$, $G$, $T1$ and $T2^\prime$ conditions in the
two-dimension al Hubbard model case and we conduct a thorough study applying
the $4\times 4$ Hubbard model employing a coefficients. Within the Hubbard
Hamilt onian we found that even in the intermediate setting, where $U/t$ is
between 4 and 10, the $P$, $Q$, $G$, $T1$ and $T2^\prime$ conditions re
produced good ground state energies.

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The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
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The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
19
The categories of this paper are: eess
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The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
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The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
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The categories of this paper are: chem-ph
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The categories of this paper are: atom-ph