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JOURNALS // Symmetry, Integrability and Geometry: Methods and Applications // Archive

SIGMA, 2025 Volume 21, 010, 21 pp. (Mi sigma2127)

Fermionic Basis in Conformal Field Theory and Thermodynamic Bethe Ansatz for Excited States II

Sergei Adler, Hermann Boos

Fakultät für Mathematik und Naturwissenschaften, Bergische Universität Wuppertal, 42097 Wuppertal, Germany

Abstract: We consider the XXZ spin chain in the scaling limit in the Matsubara direction. The main result of this paper is new representations for the functions $\Psi(l, \kappa)$ and $\Theta(l, m; \kappa, \alpha)$ associated with the function $\omega(\zeta, \xi; \kappa, \kappa)$ found in the expression for the correlation function of the generators of the fermionic basis for the XXZ spin chain. The final result incorporates the case of particle-hole excitations which is needed for the relation of the fermionic basis to the Virasoro basis of the CFT descendants.

Keywords: integrable models, six-vertex model, XXZ spin chain, thermodynamic Bethe ansatz, fermionic basis, excited states, conformal field theory, Virasoro algebra.

MSC: 82B20, 82B21, 82B23, 81T40, 81Q80

Received: July 3, 2024; in final form February 7, 2025; Published online February 16, 2025

Language: English

DOI: 10.3842/SIGMA.2025.010


ArXiv: 2312.15522


© Steklov Math. Inst. of RAS, 2025