Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Efficient numerical solver for first-principles transport calculation
  based on real-space finite-difference method   We propose an efficient procedure to obtain Green's functions by combining
the shifted conjugate orthogonal conjugate gradient (shifted COCG) method with
the nonequilibrium Green's function (NEGF) method based on a real-space
finite-difference (RSFD) approach. The bottleneck of the computation in the
NEGF scheme is matrix inversion of the Hamiltonian including the self-energy
terms of electrodes to obtain perturbed Green's function in the transition
region. This procedure first computes unperturbed Green's functions and
calculates perturbed Green's functions from the unperturbed ones using a
mathematically strict relation. Since the matrices to be inverted to obtain the
unperturbed Green's functions are sparse, complex-symmetric and shifted for a
given set of sampling energy points, we can use the shifted COCG method, in
which once the Green's function for a reference energy point has been
calculated, the Green's functions for the other energy points can be obtained
with a moderate computational cost. We calculate the transport properties of a
C$_{60}$@(10,10) carbon nanotube (CNT) peapod suspended by (10,10)CNTs as an
example of a large-scale transport calculation. The proposed scheme opens the
possibility of performing large-scale RSFD-NEGF transport calculations using
massively parallel computers without the loss of accuracy originating from the
incompleteness of the localized basis set.

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The categories of this paper are: q-bio
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The categories of this paper are: plasm-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: adap-org
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The categories of this paper are: acc-phys
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The categories of this paper are: eess
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-th
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The categories of this paper are: q-fin
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The categories of this paper are: patt-sol
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The categories of this paper are: solv-int
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The categories of this paper are: cs
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-ex
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The categories of this paper are: math-ph