Regensburg 2019 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 31: Nonlinear Dynamics, Synchronization and Chaos
DY 31.7: Vortrag
Mittwoch, 3. April 2019, 11:45–12:00, H20
Temperature dependence of butterfly effect in a classical many-body system — •Thomas Bilitewski1, Subhro Bhattacharjee2, and Roderich Moessner1 — 1Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Str. 38, 01187 Dresden, Germany — 2International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, Bengaluru 560089, India
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 ∼ T−1. 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.