2018/08/16 by Thomas Bilitewski, Subhro Bhattacharjee, Roderich Moessner · 1 citation
Physics and Astronomy · #cond-mat.stat-mech
paper · pdf · doi:10.1103/physrevlett.121.250602
published as Phys. Rev. Lett. 121, 250602 (2018) · 6+4 pages, 4+8 figures, ancillary files include videos of the dynamics
arxiv created 2018/08/16 · arxiv updated 2018/12/26
We study the chaotic dynamics in a classical many-body system of interacting spins on the kagome lattice. We characterise many-body chaos via the butterfly effect as captured by an appropriate out-of-time-ordered correlator. Due to the emergence of a spin liquid phase, the chaotic dynamics extends all the way to zero temperature. We thus determine the full temperature dependence of two complementary aspects of the butterfly effect: the Lyapunov exponent, μ, and the butterfly speed, vb, and study their interrelations with usual measures of spin dynamics such as the spin-diffusion constant, D and spin-autocorrelation time, τ. We find that they all exhibit power law behaviour at low temperature, consistent with scaling of the form D∼ vb2/μ and τ-1∼ T. The vanishing of μ∼ T0.48 is parametrically slower than that of the corresponding quantum bound, μ∼ T, raising interesting questions regarding the semi-classical limit of such spin systems.