SKM 2023 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 43: Poster: Correlated Electrons II

TT 43.17: Poster

Mittwoch, 29. März 2023, 15:00–18:00, P2/OG3

Exact diagonalization with twisted boundary conditions — •Benjamin Heinrich — Institut für funktionelle Materie und Quantentechnologie, Universität Stuttgart

When using exact diagonalization, using twisted instead of periodic boundary conditions gives access to additional momentum points. We investigate here in detail flavour-specific twisted boundary conditions, where each spin and /or orbital can have different boundary conditions. One goal is to assess whether and to which extent this improves estimates of observables (e.g. the ground-state energy). As increased momentum resolution is of particular interest in excitation spectra, a second aim is to estimate the quality of these additional data. We investigate the method for one- and two-dimensional one- and two-band Hubbard models. First results suggest that the additional momenta work well where the relevant physics is to a large extent captured by one quasiparticle (e.g. the magnon in case of magnetic spectra), but are less reliable in more complex scenarios (e.g. two spinons).