Related papers: Can oscillating scalar fields decay into particles…
We study the quantum fluctuations of scalar fields with a variable effective mass during an inflationary phase. We consider the situation where the effective mass depends on a background scalar field, which evolves during inflation from…
Oscillons are extremely long-lived, spatially-localized field configurations in real-valued scalar field theories that slowly lose energy via radiation of scalar waves. Before their eventual demise, oscillons can pass through (one or more)…
Standard decoupling of heavy fermions may fail when there are non-perturbative variations in a scalar field which gives masses to the fermions. One situation of phenomenological relevance is the case of sphalerons in the presence of…
We present a numerical integration of the cosmological scalar perturbation equations in warm inflation. The initial conditions are provided by a discussion of the thermal fluctuations of an inflaton field and thermal radiation using a…
Dissipative effects can lead to a friction term in the equation of motion for an inflaton field during the inflationary era. The friction term may be linear and localised, in which case it is described by a dissipation coefficient. The…
If the inflaton is a heavy scalar field, it may equilibrate slower than some other degrees of freedom, e.g. non-Abelian gauge bosons. In this case, perturbations in the inflaton field and in a thermal plasma coexist from a given moment…
Inflation has long been the accepted paradigm for understanding the early universe. Most models of inflation have a scalar field acting as the inflaton particle which decays after inflation during a process called reheating into standard…
We study the thermodynamic behavior of a decaying scalar field coupled to a relativistic simple fluid. It is shown that if the decay products are represented by a thermalized bath, its temperature evolution law requires naturally a new…
We consider the inflaton as a scalar field described by a non-minimal derivative coupling model with a power law potential. We study the slow roll inflation, the rapid oscillation phase, the radiation dominated and the recombination eras…
During the last ten years a detailed investigation of preheating was performed for chaotic inflation and for hybrid inflation. However, nonperturbative effects during reheating in the new inflation scenario remained practically unexplored.…
One of the fundamental problems of modern cosmology is to explain the origin of all the matter and radiation in the Universe today. The inflationary model predicts that the oscillations of the scalar field at the end of inflation will…
We analyze the dynamics of models of warm inflation with general dissipative effects. We consider phenomenological terms both for the inflaton decay rate and for viscous effects within matter. We provide a classification of the asymptotic…
We consider a multiverse scenario made up of classically disconnected regions of the space-time that are, nevertheless, in a quantum entangled state. The addition of a scalar field enriches the model and allows us to treat both the…
This paper extends the study of the quantum dissipative effects of a cosmological scalar field by taking into account the cosmic expansion and contraction. Cheung, Drewes, Kang and Kim calculated the effective action and quantum dissipative…
I study the post-inflation oscillation and decay of light coherent scalar field condensates that may develop during an inflationary phase of the universe. In particular, the light scalars studied are a composition of the scalar particles of…
We study the evolution of cosmological fluctuations during and after inflation driven by a scalar field coupled to a perfect fluid through afriction term. During the slow-roll regime for the scalar field, the perfect fluid is also frozen…
Dynamics of the inflaton scalar field oscillating around a minimum of the singular potentials in the expanding Universe is investigated. Asymptotic formulas are obtained describing the cosmological expansion at the late times. The problem…
We compute the decay rate of a metastable cosmic string in contact with a thermal bath by finding the instanton solution. The new feature is that this decay rate is found in the context of non thermal scalar fields in contact with a thermal…
We present a study of the decay of metastable states of a scalar field via thermal activation, in the presence of a finite density of fermions. The process we consider is the nucleation of ``{\it droplets}'' of true vacuum inside the false…
The time dependence of the temperature during the reheating process is studied. We consider the thermal feedback effects of the produced particles on the effective dissipation rate of the inflaton field, which can lead to enhanced…