Related papers: Analytic Approximations for Fermionic Preheating
We revisit the non-thermal dark matter (DM) production during the thermalization and reheating era after inflation. The decay of inflaton produces high-energy particles that are thermalized to complete the reheating of the Universe. Before…
The excessive production of gravitinos in the early universe destroys the successful predictions of nucleosynthesis. The thermal generation of gravitinos after inflation leads to the bound on the reheating temperature, T_{RH}< 10^9 GeV.…
We consider the resonant production of fermions from an oscillating axial background. The classical evolution of the axial field is given by that of a massive pseudovector field, as suggested by the renormalizability of the theory. We look…
Field amplification and particle production due to parametric resonance are highly nontrivial predictions of quantum fields that couple to an oscillating source during inflation and reheating. Understanding this two effects is crucial for…
Hot axions, thermally produced in the Early Universe, would contribute to dark radiation and are thus subject to present and future constraints from $N_{\rm eff}$. In this paper we quantify the contribution to $N_{\rm eff}$ and its…
Recent measurements from the Atacama Cosmology Telescope (ACT), combined with Planck and DESI data, suggest a scalar spectral index $n_s$ higher than the Planck 2018 baseline, thereby placing conventional attractor-type inflationary models…
We consider the planar local patch approximation of $d=2$ fermions at finite density coupled to a critical boson. In the quenched or Bloch-Nordsieck approximation, where one takes the limit of fermion flavors $N_f\rightarrow 0$, the fermion…
We study preheating in DBI hybrid inflation. Preheating occurs since the matter fields are non-minimally coupled to the inflaton. Despite the coupling being small, preheating happens as a narrow parametric resonance in which matter fields…
Non-thermal histories for the early universe have received notable attention as they are a rich source of phenomenology, while also being well motivated by top-down approaches to beyond the Standard Model physics. The early (pre-BBN) matter…
We show that warm inflation can be successfully realized in the high temperature regime through dissipative interactions between the inflaton and a single fermionic degree of freedom, provided that the latter's mass is an oscillatory…
Processes of particle production during inflation can increase the amplitude of the scalar metric perturbations. We show that such a mechanism can naturally arise in supergravity models where an axion-like field, whose potential is…
We propose an alternate, calculable mechanism of dark matter genesis, "thermal freeze-in," involving a Feebly Interacting Massive Particle (FIMP) interacting so feebly with the thermal bath that it never attains thermal equilibrium. As with…
A novel method to determine the density and temperature of a system based on quantum Fermionic fluctuations is generalized to the limit where the reached temperature T is large compared to the Fermi energy {\epsilon}f . Quadrupole and…
I report on work done with Tomislav Prokopec (Heidelberg, CERN). We computed the one loop self-energy of a massless fermion during inflation. When the fermion is free it experiences only a small amount of inflationary particle production…
We study the dynamical generation of masses for fundamental fermions in quenched quantum electrodynamics (qQED) at finite temperature in the bare vertex approximation, using Schwinger-Dyson equations (SDE). Motivated by perturbation theory,…
A consistent nonperturbative approach (based on QFT) to neutral fermion creation (due to their magnetic moments) in strong inhomogeneous magnetic fields is considered. It is demonstrated that quantization in terms of neutral particles and…
The most widely studied scenario in dark matter phenomenology is the thermal WIMP scenario. Inspite of numerous efforts to detect WIMP, till now we have no direct evidence for it. A possible explanation for this non-observation of dark…
We investigate a simple extension of the standard model (SM) in which the dark matter consists of a feebly interacting fermion (FIMP), charged under a new $Z_4$ symmetry, that is produced in the early Universe by the freeze-in mechanism.…
The Thomas-Fermi model at finite temperature is extended to describe a system of self-gravitating weakly interacting massive fermions in a general-relativistic framework. By cooling a nondegenerate gas of weakly interacting massive fermions…
We investigate for viable models of inflation that can successfully produce dark matter (DM) from inflaton decay process, satisfying all the constraints from Cosmic Microwave Background (CMB) and from some other observations. In particular,…