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arXiv · 2604.27730

Non-Gaussian hydrodynamic fluctuations in an expanding relativistic fluid

Gokce Basar·Shuo Song
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Abstract

We consider non-equilibrium evolution of non-Gaussian fluctuations in a hydrodynamic system undergoing a boost-invariant expansion described by Bjorken flow. We derive the evolution equations for two- and three-point velocity correlators using the effective field theory framework and present analytical solutions for them. We show that the average Landau frame is better suited for studying non-Gaussian fluctuations of velocity when relativistic effects are important. In the Bjorken background, the average Landau frame corresponds to the density frame. We demonstrate that the three-point correlators depend nonlinearly on the non-equilibrium dynamics of the two-point functions, and exhibit non-trivial effects such as memory. The importance of these effects in the context of the search for the QCD critical point via fluctuations is discussed.

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Gokce Basar, Shuo Song. 2026-04-30. Non-Gaussian hydrodynamic fluctuations in an expanding relativistic fluid. https://doi.org/10.1103/hzvz-yfg1

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