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TT: Fachverband Tiefe Temperaturen

TT 80: Correlated Electrons: Poster

TT 80.43: Poster

Thursday, March 21, 2024, 15:00–18:00, Poster E

Multipartite entanglement in the spin-1 bilinear-biquadratic chain — •Malo Rouxel and Andreas Honecker — Laboratoire de Physique Théorique et Modélisation, CNRS UMR 8089, CY Cergy Paris Université, France

The spin-1 bilinear-biquadratic chain represents the most general model for an isotropic exchange interaction in a spin-1 chain. In this model, the Hamiltonian can be expressed as a function of θ:

H =

∑

(cos(θ)(S_iS_i+1) + sin(θ)(S_iS_i+1)²).

The chain exhibits several phases depending on the value of θ: the Haldane phase, a dimerized phase, a ferromagnetic phase, and a gapless phase. We show that proper multipartite entanglement measures enable the differentiation of various behaviors of the ground state depending on θ, and thus the identification of the corresponding phases. This ground state is obtained by diagonalizing the Hamiltonian using the Lanczos algorithm and the divide-and-conquer eigenvalue algorithm. As the ground state can be degenerate, symmetries and conservation laws are also studied.

Keywords: Spin 1 Chain; Quantum Entanglement; Exact Diagonalization