Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 53: Low-Dimensional Systems: 1D - Theory

TT 53.4: Vortrag

Mittwoch, 9. März 2016, 15:45–16:00, H23

Quantum Monte Carlo studies of the spin dynamics in the spin-1 Heisenberg chain — •Jonas Becker and Stefan Wessel — Institut für Theoretische Festkörperphysik, JARA-FIT and JARA-HPC, RWTH Aachen University, 52056 Aachen, Germany

The dynamic spin structure factor S(k,ω) of the antiferromagnetic isotropic spin S=1 Heisenberg chain is studied at finite temperature. Quantum Monte Carlo simulations with the stochastic series expansion scheme are performed to extract this dynamic observable for individual Matsubara frequencies. Then a stochastic analytic continuation method is applied to extract the real-frequency spin structure factor from the imaginary frequency data. Simulations for low temperatures are performed with high accuracy and the results are compared to DMRG data [1]. We also focus on the spectrum’s multi-magnon continuum and show that performing the analytic continuation in the over-fitting regime produces additional features therein. Finally, the temperature dependence of the dynamic spin structure factor S(k,ω) is presented.

[1] S. White and I. Affleck. PRB 77, 134437 (2008)