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arXiv · 2402.06776

Consistent inclusion of fluctuations in first-order causal and stable relativistic hydrodynamics

Lorenzo Gavassino·Nicki Mullins·Mauricio Hippert
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Abstract

We construct, for the first time, a Bemfica-Disconzi-Noronha-Kovtun (BDNK) theory for linear stochastic fluctuations, which is proved to be mathematically consistent, causal, and covariantly stable. The Martin-Siggia-Rose action is shown to be bilocal in most cases, and the noise is not white. The presence of nonhydrodynamic modes induces long-range correlations in the primary fluid variables (temperature, chemical potential, and flow velocity). However, correlators of conserved densities remain localized in space, and coincide with those calculated within fluctuating Isreal-Stewart theory. We show that, in some cases, there is a nonlocal change of variables that maps the Israel-Stewart action into the BDNK action.

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Lorenzo Gavassino, Nicki Mullins, Mauricio Hippert. 2024-02-09. Consistent inclusion of fluctuations in first-order causal and stable relativistic hydrodynamics. https://doi.org/10.1103/physrevd.109.125002

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