Hydrodynamic Gradient Expansion Diverges beyond Bjorken Flow.

  title={Hydrodynamic Gradient Expansion Diverges beyond Bjorken Flow.},
  author={Michal P. Heller and Alexandre Serantes and Michal Spali'nski and Viktor Svensson and Benjamin Withers},
  journal={Physical review letters},
  volume={128 12},
The gradient expansion is the fundamental organizing principle underlying relativistic hydrodynamics, yet understanding its convergence properties for general nonlinear flows has posed a major challenge. We introduce a simple method to address this question in a class of fluids modeled by Israel-Stewart-type relaxation equations. We apply it to (1+1)-dimensional flows and provide numerical evidence for factorially divergent gradient expansions. This generalizes results previously only obtained… 

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