Spectral properties of the spin-1 bilinear-biquadratic Heisenberg and the Hubbard-Holstein model

NAISS 2023/22-527


NAISS Small Compute

Principal Investigator:

Thomas Köhler


Uppsala universitet

Start Date:


End Date:


Primary Classification:

10304: Condensed Matter Physics



Doing time evolution of quantum systems with large local bond dimension is hard. After proposing ppDMRG [1] it became a little bit easier, but if one is only interested in spectral functions a possibly less demanding approach is to use the Chebyshev expansion [2]. This project aims at understanding the limitations with respect to an energy truncation. Furthermore, the investigation of the spin-1 bilinear-biquadratic Heisenberg model is not finished since for the determination of the order of the critical-to-ferromagnetic phase transition high-precision results in the area close to this transition are needed. Our up-to-date results in this area lack precision due to rapid growth of the correlation length in the system. Appropriate calculations require large amount of RAM, which makes access to `fat' nodes on Rackham essential. [1] (accepted) [2]