Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hydrodynamic Gradient Expansion Diverges beyond Bjorken Flow   The gradient expansion is the fundamental organising 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 modelled by
Israel-Stewart--type relaxation equations. We apply it to (1+1)-dimensional
flows and provide numerical evidence for factorially divergent gradient
expansions. This generalises results previously only obtained for
(0+1)-dimensional comoving flows, notably Bjorken flow. We also demonstrate
that the only known nontrivial case of a convergent hydrodynamic gradient
expansion at the nonlinear level relies on Bjorken flow symmetries and becomes
factorially divergent as soon as these are relaxed. Finally, we show that
factorial divergence can be removed using a momentum space cutoff, which
generalises a result obtained earlier in the context of linear response.

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The categories of this paper are: acc-phys
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The categories of this paper are: bayes-an
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-fin
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The categories of this paper are: math-ph
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The categories of this paper are: solv-int
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The categories of this paper are: funct-an
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The categories of this paper are: gr-qc
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The categories of this paper are: chem-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: cs
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The categories of this paper are: nlin
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The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg