In talk I will show how to self-consistently couple the Einstein-inflaton equations to a strongly coupled quantum field theory (QFT) as described by holography. We show that this can lead to an inflating universe, a reheating phase and finally a universe dominated by the QFT in thermal equilibrium. Special attention will be given to technical details that could be of relevance for modelling of...
Axion inflation coupled to Abelian gauge fields via a Chern-Simons-like term presents an attractive inflationary model with rich phenomenology, including the production of magnetic fields, black holes, gravitational waves, and possible links to the matter-antimatter asymmetry. In my talk, I will discuss a particular regime of axion inflation, the so-called Anber-Sorbo solution. In this...
Gravitational particle production of spectator fields due to the expansion universe during the inflationary and reheating phases of the early universe is of particular interest in the context of dark matter, since it allows to constrain the properties of the dark candidate by comparing the density of particles produced with the observed dark matter abundance. In such processes, tachyonic...
The phenomenon of cosmological gravitational particle production (CGPP) occurs during and after inflation as quantum fields “feel” the cosmological expansion are excited out of their ground state. CGPP is a compelling and minimal explanation for the origin of dark matter, which might only interact gravitationally, as well as other cosmological relics. In this talk, I’ll provide a general...
This session will be a guided discussion led by Lorenzo Sorbo. He will start with a visionary talk. Following this, he will engage the audience by posing stimulating questions to stimulate further
In this talk, I describe the use of numerical relativity simulations to study the non-perturbative evolution of inflationary fluctuations during preheating. We find that gravity can enhance the growth of density perturbations, which then collapse and virialize, forming long-lived stable oscillon-like stars. We quantify the compactness of these objects and find that whilst gravitational effects...
Inflationary models with significant amplification of small-scale scalar and tensor perturbations have attracted considerable attention in the literature due to their interesting observational signatures, such as primordial black holes and gravitational waves. However, the large enhancement of fluctuations often challenges our perturbative understanding of inflation. I will present a numerical...
In this talk, I will address the issue of the strong backreaction regime in the abelian axion inflation scenario. I will review our latest work on lattice simulations of the model, where we present a complete framework to simulate this model. Our work demonstrates that inhomogeneities generated during the evolution at the latest stages of inflation are specially relevant to provide a correct...
This session will be a guided discussion led by Daniel Figueroa. He will start with a visionary talk and introduction to Cosmo-Lattice. Following this, he will engage the audience by posing stimulating questions to stimulate further discussion.
I analyze the evolution of axion inflation, with gauge fields exponentially amplified by the inflaton velocity. I first review the resulting dynamics, that may lead to friction and oscillations in the inflaton trajectory. I discuss then the effects of interactions of the gauge fields: self-interactions, mediated by the axial coupling, or with Standard model fields. We show that scattering...
An axion-like inflaton coupling to a non-Abelian gauge sector leads to a scenario which may involve fast thermalization, a computable friction coefficient, control over backreaction effects, and gravitational wave production in various frequency domains. The physics depends on the confinement scale of the non-Abelian sector, and can be either weakly or strongly coupled. We review the main...
Axion-like particles with a coupling to non-Abelian gauge fields at finite temperature can experience dissipation due to sphaleron heating. This could play an important role for warm inflation or dynamical dark energy. We investigate to what degree the efficiency of this non-perturbative effect depends on the details of the underlying particle physics model. For a wide range of scenarios and...
Coupling an axion to pure Yang-Mills gauge bosons is a compelling setup for warm inflationary dynamics. The axion, a pseudo-Goldstone boson acting as the warm inflaton is protected from thermal corrections to its mass due by its approximate shift symmetry. Simultaneously, real time sphaleron processes due to the non-trivial topology of the gauge theory fuel particle production, leading to the...
