Anisotropic Landau-Lifshitz model in discrete space-time

We construct an integrable lattice model of classical interacting spins in discrete space-time, representing a discrete-time analogue of the lattice Landau-Lifshitz ferromagnet with uniaxial anisotropy. As an application we use this explicit discrete symplectic integration scheme to compute the spin Drude weight and diffusion constant as functions of anisotropy and chemical potential. We demonstrate qualitatively different behavior in the easy-axis and the easy-plane regimes in the non-magnetized sector. Upon approaching the isotropic point we also find an algebraic divergence of the diffusion constant, signaling a crossover to spin superdiffusion.

Automated summary

Researchers constructed an integrable lattice model of classical interacting spins in discrete space-time, and used an explicit discrete symplectic integration scheme to compute the spin Drude weight and diffusion constant, revealing qualitatively different behavior under different anisotropy conditions and a crossover to spin superdiffusion near the isotropic point.