Starts 14 May 2019 11:00
Ends 14 May 2019 12:00
Central European Time
SISSA, Via Bonomea 265
Universal Dynamics near Non-Thermal Fixed Points and Quantum Turbulence Abstract: Quenched or continuously driven quantum systems can show universal dynamics near non-thermal fixed points, generically in the form of scaling behaviour in space and time. Key aspects of the theory of non-thermal fixed points will be briefly summarized [1,2], as well as recent experimental results for quenched systems [3,4]. In a dilute Bose gas, universal scaling dynamics can be due to both, linear and non-linear excitations of the system. Considering scaling transport of excitations to larger wave numbers similar to an inverse cascade, the underlying excitations can be either irregular phase excitations or (quasi) topological defects exhibiting the implications for quantum turbulence. As an example, strongly anomalous scaling of inverse transport in a two-dimensional superfluid due to higher-order vortex annihilation will be discussed both, from the theoretical [5] and experimental point of view.

[1] C.-M. Schmied, A. N. Mikheev, T. Gasenzer, Non-thermal fixed points: Universal dynamics far from equilibrium, arXiv:1810.08143 [cond-mat.quant-gas]
[2] A. N. Mikheev, C.-M. Schmied, T. Gasenzer, Low-energy effective theory of non- thermal fixed points in a multicomponent Bose gas, arXiv:1807.10228 [cond-mat.quant-gas]
[3] M. Prüfer, P. Kunkel, H. Strobel, S. Lannig, D. Linnemann, C.-M. Schmied, J. Berges, T. Gasenzer, M.K. Oberthaler, Observation of universal dynamics in a spinor Bose gas far from equilibrium, Nature 563, 217 (2018).
[4] S. Erne, R. Bücker, T. Gasenzer, J. Berges and J. Schmiedmayer, Universal dynamics in an isolated one-dimensional Bose gas far from equilibrium, Nature 563, 225 (2018).
[5] M. Karl and T. Gasenzer, Strongly anomalous non-thermal fixed point in a quenched two-dimensional Bose gas, New J. Phys. 19, 093014 (2017).