Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 65: Low-Dimensional Systems: 1D – Theory
TT 65.9: Talk
Wednesday, March 18, 2015, 17:30–17:45, H 0104
Spectral functions of one-dimensional quantum magnets — •Alexander C. Tiegel1, Salvatore R. Manmana1, Thomas Pruschke1, and Andreas Honecker2 — 1Institut für Theoretische Physik, Georg-August-Universität Göttingen, Germany — 2LPTM, Université de Cergy-Pontoise, France
We present numerical results for experimentally relevant spectral functions of one-dimensional strongly correlated quantum systems. We focus on the electron spin resonance (ESR) modes of spin-1/2 XXZ Heisenberg chains with Dzyaloshinskii-Moriya interactions in magnetic fields at both zero and finite temperature. The spectral functions are computed directly in the frequency domain via a Chebyshev expansion of the Green's function in a density-matrix renormalization group (DMRG) framework using matrix product states (MPS). At finite temperature, the method is based on a purification of the density operator by exploiting a Liouville space formulation of the dynamics. Our results are compared to field-theoretical descriptions from the literature.