Regensburg 2022 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 24: Quantum-Critical Phenomena

TT 24.12: Vortrag

Mittwoch, 7. September 2022, 18:00–18:15, H23

Finite size spectrum of the staggered six-vertex model with U_q(sl(2))-invariant boundary conditions — •Sascha Gehrmann¹ and Holger Frahm² — ¹Institute of Theoretical Physics, Leibniz University Hannover, Germany — ²Institute of Theoretical Physics, Leibniz University Hannover, Germany

The finite-size spectrum of the critical Z₂-staggered spin-1/2 XXZ model with quantum group invariant boundary conditions is presented. The conformal weights, which are found to have a continuous component, can be described in terms of the non-compact SU(2,R)/U(1) Euclidean black hole conformal field theory (CFT) for a range of the staggering parameter. Besides the continuous part of the spectrum of this CFT, we find also levels from the discrete part emerging as the anisotropy is lowered. The finite size amplitudes of both the continuous and the discrete levels can be parameterized by the corresponding eigenvalues of a quasi-momentum operator which commutes with the Hamiltonian and the transfer matrix of the model.