Anisotropic Landau-Lifshitz model in discrete space-time

Žiga Krajnik (1) , Enej Ilievski (1) , Tomaz Prosen (1) , Vincent Pasquier (2)

1 FMF - Faculty of Mathematics and Physics [Ljubljana]
2 IPHT - Institut de Physique Théorique - UMR CNRS 3681

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.

Domaines: Physique [physics]

Žiga Krajnik, Enej Ilievski, Tomaz Prosen, Vincent Pasquier. Anisotropic Landau-Lifshitz model in discrete space-time. SciPost Physics, 2021, 11 (3), pp.051. ⟨10.21468/SciPostPhys.11.3.051⟩. ⟨cea-04525448⟩