Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 62: Correlated Electrons – Poster II

TT 62.11: Poster

Mittwoch, 11. März 2026, 15:00–17:00, P4

Low-dimensional critical behavior of correlated electrons, Mermin-Wagner theorem, and local self-energy — •Šimon Kos¹, Sunil D'Souza¹, Jan Gebel¹, Ján Minár¹, and Václav Janiš² — ¹University of West Bohemia, Univerzitní 8, CZ-301 00 Plzeň, Czech Republic — ²Institute of Physics, The Czech Academy of Sciences, Na Slovance 2, CZ-182 00 Praha 8, Czech Republic

We present a theoretical treatment of low-dimensional critical behavior coming from electron correlations. The treatment is based on the Baym-Kadanoff approach, which involves one-particle self-consistency between the propagator and the self-energy, along with the bare two-particle interaction. In low dimensions, self-consistency prevents ordering in agreement with the Mermin-Wagner theorem and exhibits critical behavior as the temperature is lowered towards zero. The critical behavior enables the use of the polar approximation, which reduces the convolutive Schwinger-Dyson equation to an algebraic equation for the local propagator and self-energy, amenable to solution. We demonstrate the treatment using the example of a 1d Hubbard model with an attractive interaction, which describes the tendency toward superconductivity, in the FLEX approximation. We present various features of the algebraic Schwinger-Dyson equation and the quantities that enter it.

Keywords: Critical behavior of correlated electrons; Mermin-Wagner theorem; Baym-Kadanoff approach; one-particle self-consistency; polar approximation