3 papers
math.AP2025
A critical threshold for the cosmological Euler-Poisson system
David Fajman, Maciej Maliborski, Maximilian Ofner +2
We consider the gravitational Euler-Poisson system with a linear equation of state on an expanding cosmological model of the Universe. The expansion of the spatial sections introdu…
gr-qc2025
Stability of fluids in spacetimes with decelerated expansion
David Fajman, Maximilian Ofner, Todd Oliynyk +1
We prove the nonlinear stability of homogeneous barotropic perfect fluid solutions in fixed cosmological spacetimes undergoing decelerated expansion. The results hold provided a sp…
gr-qc2024
Phase transition between shock formation and stability in cosmological fluids
David Fajman, Maciej Maliborski, Maximilian Ofner +2
We demonstrate a novel phase transition from stable to unstable fluid behaviour for fluid-filled cosmological spacetimes undergoing decelerated expansion. This transition occurs wh…