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@ARTICLE{Ghanem:873781,
author = {Ghanem, Khaldoon and Koch, Erik},
title = {{A}verage spectrum method for analytic continuation:
{E}fficient blocked-mode sampling and dependence on the
discretization grid},
journal = {Physical review / B},
volume = {101},
number = {8},
issn = {2469-9950},
address = {Woodbury, NY},
publisher = {Inst.},
reportid = {FZJ-2020-00995},
pages = {085111},
year = {2020},
abstract = {The average spectrum method is a promising approach for the
analytic continuation of imaginary time or frequency data to
the real axis. It determines the analytic continuation of
noisy data from a functional average over all admissible
spectral functions, weighted by how well they fit the data.
Its main advantage is the apparent lack of adjustable
parameters and smoothness constraints, using instead the
information on the statistical noise in the data. Its main
disadvantage is the enormous computational cost of
performing the functional integral. Here we introduce an
efficient implementation, based on the singular value
decomposition of the integral kernel, eliminating this
problem. It allows us to analyze the behavior of the average
spectrum method in detail. We find that the discretization
of the real-frequency grid, on which the spectral function
is represented, biases the results. The distribution of the
grid points plays the role of a default model while the
number of grid points acts as a regularization parameter. We
give a quantitative explanation for this behavior, point out
the crucial role of the default model and provide a
practical method for choosing it, making the average
spectrum method a reliable and efficient technique for
analytic continuation.},
cin = {JSC},
ddc = {530},
cid = {I:(DE-Juel1)JSC-20090406},
pnm = {511 - Computational Science and Mathematical Methods
(POF3-511)},
pid = {G:(DE-HGF)POF3-511},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000512773800002},
doi = {10.1103/PhysRevB.101.085111},
url = {https://juser.fz-juelich.de/record/873781},
}