KIP publications

year 2018
author(s) Christian-Marcel Schmied, Maximilian Prüfer, Markus K. Oberthaler and Thomas Gasenzer
title Bidirectional universal dynamics in a spinor Bose gas close to a nonthermal fixed point
KIP-Nummer HD-KIP 18-171
KIP-Gruppe(n) F17,F20,F27
document type Paper
source Phys. Rev. A 99 (2019) 033611, arXiv:1812.08571
doi 10.1103/PhysRevA.99.033611
Abstract (en)

We numerically study the universal scaling dynamics of an isolated one-dimensional ferromagnetic spin-1 Bose gas. Preparing the system in a far-from-equilibrium initial state, simultaneous coarsening and refining is found to enable and characterize the approach to a nonthermal fixed point. A macroscopic length scale which scales in time according to LΛ(t)tβ, with β?1/4, quantifies the coarsening of the size of spin textures. At the same time kinklike defects populating these textures undergo a refining process measured by a shrinking microscopic length scale Lλtβ, with β?0.17. The combination of these scaling evolutions enables particle and energy conservation in the isolated system and constitutes a bidirectional transport in momentum space. The value of the coarsening exponent β suggests the dynamics to belong to the universality class of diffusive coarsening of the one-dimensional XY model. However, the universal momentum distribution function exhibiting nonlinear transport marks the distinction between diffusive coarsening and the approach of a nonthermal fixed point in the isolated system considered here. This underlines the importance of the universal scaling function in classifying nonthermal fixed points. Present-day experiments with quantum gases are expected to have access to the predicted bidirectional scaling.

  author   = {Schmied, Christian-Marcel and Pr\"ufer, Maximilian and Oberthaler, Markus K. and Gasenzer, Thomas},
  title    = {Bidirectional universal dynamics in a spinor Bose gas close to a nonthermal fixed point},
  journal  = {Phys. Rev. A},
  year     = {2019},
  volume   = {99},
  pages    = {033611},
  month    = {Mar},
  note     = {arXiv:1812.08571},
  doi      = {10.1103/PhysRevA.99.033611},
  url      = {}
URL doi:10.1103/PhysRevA.99.033611
URL arXiv:1812.08571 [cond-mat.quant-gas]
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