Robust hydrodynamic simulations are necessary for placing strong constraints on cosmological parameters through the analysis pipelines of observations of statistics such as galaxy clustering. However, for these purposes, the simulations need both large box size and high resolution, which is computationally prohibitive. In this work we use the connection between galaxies and their host dark...
The latest DESI DR2 BAO data favor a dynamical dark energy equation of state, reviving the question of whether late-time modifications of gravity can ease the tensions of the standard model. We test a generalized exponential $f(R)$ model with massive neutrinos, which produces an effective dynamical dark energy at low redshift while recovering $\Lambda$CDM at early times. Through a Bayesian...
Effective actions with higher curvature terms can have cosmological solutions exhibiting a transient phantom regime. I will discuss a generalization of multifield cosmology in the presence of a higher curvature term, namely the Gauss-Bonnet term. I will show that in this context there are novel features of the so called rapid turn regime, in which multifield models of cosmic acceleration (i.e....
The timescape cosmology returns to first principles, to explain apparent cosmic acceleration in the statistical regime of general relativity. As inhomogeneities in density and expansion grow, they back react on the average cosmic expansion, which differs from conventional FLRW models. Crucially, dynamical spatial curvature arises as time-varying gradients of the kinetic energy of expansion,...
