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  • Open Access

Non-Gaussian hydrodynamic fluctuations in an expanding relativistic fluid

Gökçe Başar* and Shuo Song†

  • *Contact author: gbasar@unc.edu
  • †Contact author: shuosong@live.unc.edu
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Phys. Rev. C 114, 034917 – Published 25 September, 2026

DOI: https://doi.org/10.1103/hzvz-yfg1

Abstract

We consider nonequilibrium 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 nonequilibrium dynamics of the two-point functions and exhibit nontrivial 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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Non-Gaussian fluctuations in relativistic hydrodynamics: Confluent equations for three-point correlations

Xin An, Gökçe Başar, and Mikhail Stephanov
Phys. Rev. C 114, 034916 (2026)

Article Text

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Phys. Rev. C 114, 034917– Published 25 September, 2026
  • Received 15 May 2026
  • Accepted 30 July 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.

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