## Abstract

We establish global regularity and stability for the irrotational relativistic Euler equations with equation of state p¯ = Kρ¯ , where 0 < K< 1 / 3 , for small initial data in the expanding direction of FLRW spacetimes of the form (R× T^{3}, - dt¯ ^{2}+ t¯ ^{2}δ_{ij}dx^{i}dx^{j}). This provides the first case of non-dust fluid stabilization by spacetime expansion where the expansion rate is of power law type but non-accelerated. In particular, the time integral of the inverse scale factor diverges as t→ ∞. The result implies that structure formation in cosmological evolution associated with the development of shocks in fluids necessarily requires a phase of deccelerating expansion of the Universe to occur in the case that the matter is massive.

Original language | English |
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Number of pages | 26 |

Journal | Communications in Mathematical Physics |

DOIs | |

Publication status | Accepted/In press - 7 Jan 2021 |