Cosmological consequences of first-order general-relativistic viscous fluid dynamics

Fábio S. Bemfica, Marcelo M. Disconzi, Jorge Noronha, Robert J. Scherrer

Research output: Contribution to journalArticlepeer-review


We investigate the out-of-equilibrium dynamics of viscous fluids in a spatially flat Friedmann-Lemaître-Robertson-Walker cosmology using the most general causal and stable viscous energy-momentum tensor defined at first order in spacetime derivatives. In this new framework a pressureless viscous fluid having equilibrium energy density ρ can evolve to an asymptotic future solution in which the Hubble parameter approaches a constant while ρ→0, even in the absence of a cosmological constant (i.e., Λ=0). Thus, while viscous effects in this model drive an accelerated expansion of the universe, the equilibrium energy density itself vanishes, leaving behind only the acceleration. This behavior emerges as a consequence of causality in first-order theories of relativistic fluid dynamics and it is fully consistent with Einstein's equations.

Original languageEnglish (US)
Article number023512
JournalPhysical Review D
Issue number2
StatePublished - Jan 15 2023
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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