Orateur
Description
We use holography to study dS-invariant states of non-conformal, strongly coupled quantum field theories in four-dimensional de Sitter space. We show that out-of-equilibrium effects can sustain exponential inflation within the regime of validity of semiclassical gravity, $H \ll M \ll M_{\text{sp}}$, where $H$ is the Hubble parameter, $M$ is the QFT characteristic scale, $M_{\text{sp}} = M_p / N$ is the species scale, $M_p$ is the Planck scale, and $N^2$ is the number of matter fields. In the holographic description, the required fine-tuning scales only logarithmically with $M_{\text{sp}} / H$, and the resulting solutions feature apparent horizons whose growing area reflects a continuous increase in comoving entropy density. Extending this framework to dynamical gravity, we demonstrate that this inflationary state emerges as the late-time attractor of an initial Friedmann--Lema\^itre--Robertson--Walker universe. Finally, we present preliminary results on a mechanism that terminates this inflationary epoch after a large number of e-foldings.