Berlin 2024 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 80: Correlated Electrons: Poster

TT 80.45: Poster

Donnerstag, 21. März 2024, 15:00–18:00, Poster E

Efficient Spin-Structure Estimation through Flavor-Specific Twisted Boundary Conditions — •Benjamin Heinrich — Institut für funktionelle Materie und Quantentechnologie, Universität Stuttgart

The challenge of constrained cluster sizes arising from the escalating computational demand of exact diagonalization (ED) can be addressed by extending periodic with twisted boundary conditions. By employing flavor-specific twisted boundary conditions, wherein each spin gains a distinct phase during hopping, additional points in momentum space become accessible when computing the spin excitation spectrum. In this study, we explore the viability of this approach by applying it to the Hubbard model on one- and two-dimensional lattices. Our findings indicate that this method produces reliable results in scenarios where the pertinent physics is predominantly captured by a single quasiparticle (e.g., one magnon), even if the relevant magnetic order is incommensurate with the bare lattice. However, its reliability diminishes in more intricate situations (e.g., two spinons). For the former case, this methodology provides a valuable initial insight into excitation spectra with minimal computational demands and can be easily integrated into existing ED code.

Keywords: Exact diagonalization; Twisted boundary conditions; Hubbard model; Dynamic spin-structure factor