Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Low Rank Approximation in $G_0W_0$ Approximation   The single particle energies obtained in a Kohn--Sham density functional
theory (DFT) calculation are generally known to be poor approximations to
electron excitation energies that are measured in transport, tunneling and
spectroscopic experiments such as photo-emission spectroscopy. The correction
to these energies can be obtained from the poles of a single particle Green's
function derived from a many-body perturbation theory. From a computational
perspective, the accuracy and efficiency of such an approach depends on how a
self energy term that properly accounts for dynamic screening of electrons is
approximated. The $G_0W_0$ approximation is a widely used technique in which
the self energy is expressed as the convolution of a non-interacting Green's
function ($G_0$) and a screened Coulomb interaction ($W_0$) in the frequency
domain. The computational cost associated with such a convolution is high due
to the high complexity of evaluating $W_0$ at multiple frequencies. In this
paper, we discuss how the cost of $G_0W_0$ calculation can be reduced by
constructing a low rank approximation to the frequency dependent part of $W_0$.
In particular, we examine the effect of such a low rank approximation on the
accuracy of the $G_0W_0$ approximation. We also discuss how the numerical
convolution of $G_0$ and $W_0$ can be evaluated efficiently and accurately by
using a contour deformation technique with an appropriate choice of the
contour.

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The categories of this paper are: econ
4
The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc
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The categories of this paper are: nucl-th
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The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: quant-ph
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The categories of this paper are: cs
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The categories of this paper are: astro-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
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The categories of this paper are: eess
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The categories of this paper are: q-bio