Quantum-classical crossover in finite spin-1/2 rings with Dzyaloshinsky-Moriya interaction

Abstract

We study finite spin-$\frac{1}{2}$ rings with nearest-neighbor Heisenberg exchange, Dzyaloshinsky--Moriya interaction, and an external magnetic field. We introduce an interpolation parameter between the fully quantum Hamiltonian and a state-dependent mean-field description. Using dissipative Gisin--Schrödinger dynamics, we analyze the resulting quantum--classical crossover through local magnetization, connected spin correlations, single-site entropy, and the saturation field of the fully polarized state.

18 pages, 3 figures. Revised version with additional references, clarification of the mean-field normalization and Lyapunov structure