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DY: Fachverband Dynamik und Statistische Physik

DY 17: Statistical Physics (General) I

DY 17.9: Vortrag

Dienstag, 2. April 2019, 12:15–12:30, H19

Low-energy physics of the bilinear-biquadratic spin-1 chain — •Moritz Binder and Thomas Barthel — Department of Physics, Duke University, Durham, North Carolina 27708, USA

The bilinear-biquadratic spin-1 chain features various interesting quantum phases, including the Haldane phase, a dimerized phase, and an extended critical phase. Here, we apply an efficient density matrix renormalization group (DMRG) algorithm utilizing infinite boundary conditions [1] to compute precise dynamic spin structure factors for a comprehensive set of points in the phase diagram. Analyzing both dynamic spin and quadrupolar correlations, we gain detailed insights into the nature of low-lying excitations of the model. We compare our results to Bethe ansatz solutions at the SU(3)-symmetric ULS point and the TB point as well as at the pure biquadratic point, which can be mapped to an anisotropic spin-1/2 XXZ chain in the gapped Néel phase. In the Haldane phase, we relate our results to the approximate description in terms of the non-linear sigma model.

[1] M. Binder and T. Barthel, Phys. Rev. B 98, 235114 (2018).