IEA PBH#2

Contribution List

1. Alireza Talebian: Stochastic effects of electromagnetic fields in the early universe

11/9/20, 2:00 PM

We extend the stochastic formalism to the setup of the models containing a U(1) gauge field such as anisotropic inflation and Primordial magnetogenesis during inflation. In this talk, we show that the stochastic noises of the electromagnetic perturbations have significant effects on the dynamics of the system. These effects can not be neglected even in the leading order in contrast with the...

2. Aritra De & Rafid Mahbub: Numerically modelling stochastic inflation

11/9/20, 2:45 PM

We present a complete numerical treatment of inflationary dynamics under the influence of stochastic corrections from sub-Hubble modes. We discuss how to exactly model the stochastic noise terms arising from the sub-Hubble quantum modes that give rise to the coarse-grained inflaton dynamics in the form of stochastic differential equations. The stochastic differential equations are solved...

3. Amin Nassiri-Rad: Stochastic non-attractor inflation

11/9/20, 4:00 PM

We extend the formalism of stochastic inflation to the setup of non-attractor inflation with a sound speed cs. We obtain the Langevin equations for the superhorizon perturbations and calculate the stochastic corrections to curvature perturbation power spectrum. It is shown that the fractional stochastic corrections in mean number of e-folds and power spectrum are at the order of power...

4. Emmanuel Frion: Stochastic Collapse

11/9/20, 4:45 PM

In this talk, I will present the consequences of applying the stochastic formalism to cosmological models described by a scalar field with an exponential potential. In particular we show that quantum field fluctuations perturb the equation of state on large scales which can lead to a quantum instability of the classical collapse solution below the Planck scale in the case of a pressureless collapse.

5. Yuichiro Tada: StocDeltaN: numerical approach to inflation in combination of the stochastic and delta N formalism

11/10/20, 10:00 AM

The stochastic approach to inflation enables us to treat the superhorizon perturbations in a non-perturbative way.
Though it deals only with the inflatons’ perturbations in itself, fluctuations in the duration of inflation
can be connected with the observable curvature perturbations from the viewpoint of the delta N formalism.
In 2015, Vennin and Starobinsky revealed the adjoint...

6. Sebastien Renaux-Petel: Multifield stochastic inflation in phase space: a manifestly covariant theory and its first principle derivation.

11/10/20, 10:45 AM

In this talk based on arXiv:2008.07497 (from Lucas Pinol, Yuichiro Tada and myself), after an introduction to stochastic inflation, I explain the difficulties and the solution to formulate this theory in a manner that respects covariance under field redefinitions. I do so in the general framework of multifield inflation with a curved field space, taking into account the coupling to gravity as...

7. Laura Iacconi: Small-Scale Tests of Inflation

11/10/20, 12:00 PM

The detection and characterisation of primordial gravitational waves produced during inflation can be an excellent test for the particle content of the very early universe. We consider an inflationary realisation whose tensor spectrum is sourced already at linear order, with a sufficient production of primordial gravitational waves to make the signal detectable at interferometer scales. We...