https://doi.org/10.1140/epjb/s10051-023-00563-6
Regular Article - Solid State and Materials
Extended quasiparticle Padé approximation for non-Fermi liquids
1
Münster University of Applied Sciences, Stegerwaldstrasse 39, 48565, Steinfurt, Germany
2
International Institute of Physics-UFRN, Campus Universitário Lagoa nova, 59078-970, Natal, Brazil
Received:
13
May
2023
Accepted:
26
June
2023
Published online:
12
July
2023
The extended quasiparticle picture is adapted to non-Fermi systems by suggesting a Padé approximation which interpolates between the known small scattering-rate expansion and the deviation from the Fermi energy. The first two energy-weighted sum rules are shown to be fulfilled independent of the interpolating function for any selfenergy. For various models of one-dimensional Fermions scattering with impurities the quality of the Padé approximation for the spectral function is demonstrated and the reduced density matrix or momentum distribution is reproduced not possessing a jump at the Fermi energy. Though the two-fold expansion is necessary to realize the spectral function and reduced density, the extended quasiparticle approximation itself is sufficient for the description of transport properties due to cancellation of divergent terms under integration. The T-matrix approximation leads to the delay time as the time two particles spend in a correlated state. This contributes to the reduced density matrix and to an additional part in the conductivity which is presented at zero and finite temperatures. Besides a localization at certain impurity concentrations, the conductivity shows a maximum at small temperatures interpreted as onset of superconducting behaviour triggered by impurities. The Tan contact reveals the same universal behaviour as known from electron–electron scattering.
The original online version of this article was revised due to a retrospective Open Access order.
A correction to this article is available online at https://doi.org/10.1140/epjb/s10051-024-00658-8.
Copyright comment corrected publication 2024
Copyright comment corrected publication 2024
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