Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Truncating the memory time in nonequilibrium DMFT calculations   The nonequilibrium Green's functions (NEGF) approach is a versatile
theoretical tool, which allows to describe the electronic structure,
spectroscopy and dynamics of strongly correlated systems. The applicability of
this method is, however, limited by its considerable computational cost. Due to
the treatment of the full two-time dependence of the NEGF the underlying
equations of motion involve a long-lasting non-Markovian memory kernel that
results in at least a $N^3_t$ scaling in the number of time points $N_t$. The
system's memory time is, however, reduced in the presence of a thermalizing
bath. In particular, dynamical mean-field theory (DMFT) -- one of the most
successful approaches to strongly correlated lattice systems - maps extended
systems to an effective impurity coupled to a bath. In this work, we
systematically investigate how the memory time can be truncated in
nonequilibrium DMFT simulations of the Hubbard and Hubbard-Holstein model. We
show that suitable truncation schemes, which substantially reduce the
computational cost, result in excellent approximations to the full time
evolution. This approach enables the propagation to longer times, making
fundamental processes like prethermalization and the final stages of
thermalization accessible to nonequilibrium DMFT.

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The categories of this paper are: cs
25
The categories of this paper are: patt-sol
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The categories of this paper are: eess
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ph
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
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The categories of this paper are: hep-ex
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The categories of this paper are: q-bio
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The categories of this paper are: adap-org
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The categories of this paper are: funct-an
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The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
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The categories of this paper are: supr-con
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The categories of this paper are: dg-ga