Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 9: Poster Session: Correlated Electrons
TT 9.31: Poster
Dienstag, 28. September 2021, 13:30–16:00, P
Accuracy of the typicality approach using Chebyshev polynomials — Florian Gayk1, Heinz-Jürgen Schmidt2, Andreas Honecker3, Jürgen Schnack4, and •Henrik Schlüter4 — 1Fakultät für Physik, Universität Bielefeld, Postfach 100131, Bielefeld D-33501, Germany — 2Fachbereich Physik, Universität Osnabrück, Osnabrück D-49069, Germany — 3Laboratoire de Physique Théorique et Modélisation, CNRS UMR 8089, CY Cergy Paris Université, Cergy-Pontoise Cedex F-95302 — 4Fakultät für Physik, Universität Bielefeld, Postfach 100131, Bielefeld D-33501, Germany
Trace estimators allow us to approximate thermodynamic equilibrium observables with astonishing accuracy. A prominent representative is the finite-temperature Lanczos method (FTLM) which relies on a Krylov space expansion of the exponential describing the Boltzmann weights. Here we report investigations of an alternative approach which employs Chebyshev polynomials [1]. This method turns out to be also very accurate in general, but shows systematic inaccuracies at low temper- atures that can be traced back to an improper behaviour of the approximated density of states with and without smoothing kernel. Applications to archetypical quantum spin systems are discussed as examples.
[1] H. Schlüter, F. Gayk, H.-J. Schmidt, A. Honecker and J. Schnack, Zeitschrift für Naturforschung A, 2021 https://doi.org/10.1515/zna-2021-0116