Related papers: Can oscillating scalar fields decay into particles…
The inflaton must convert its energy into radiation after inflation, which, in a conventional scenario, is caused by the perturbative inflaton decay. This reheating process would be much more complicated in some cases: the decay products…
We show that dissipative effects have a significant impact on the evolution of cosmological scalar fields, leading to friction, entropy production and field fluctuations. We explicitly compute the dissipation coefficient for different…
In cosmological context, classical scalar fields are important ingredients for inflation models, many candidate models of dark energy, symmetry breaking and phase transition epochs, and their consequences such as baryo and lepto-genesis. We…
The basic properties of oscillons -- localized, long-lived, time-dependent scalar field configurations -- are briefly reviewed, including recent results demonstrating how their existence depends on the dimensionality of spacetime. Their…
Particle production caused by the oscillation after inflation is important since it explains reheating after inflation. On the particle theory side, we know that effective action may have additional higher dimensional terms (usually called…
We employ a viable $f(R)$ gravity model capable of giving an inflationary phase in order to study the subsequent reheating phase due to particle creation at the expense of energy in the scalaron field. Since quantum mechanics is expected to…
At the first stage of reheating after inflation, parametric resonance may rapidly transfer most of the energy of an inflaton field $\phi$ to the energy of other bosons. We show that quantum fluctuations of scalar and vector fields produced…
We provide a detailed study of reheating in the kination regime where particle content is created by gravitational production of massive scalars mutually interacting with a massless scalar field. The produced particles subsequently decay…
The paradigm of the inflationary universe provides a possible explanation for several observed cosmological properties. In order for such solutions to be successful, the universe must convert the energy stored in the inflaton potential into…
We consider a (1+1) dimensional scalar field theory that supports oscillons, which are localized, oscillatory, stable solutions to nonlinear equations of motion. We study this theory in an expanding background and show that oscillons now…
We study a model for reheating that has been much investigated for parametric resonance, having a quartic interaction of the scalar inflaton with another scalar field. Attention is particularly on the quantum excitations of the inflaton…
Quantum dissipation in thermal environment is investigated, using the path integral approach. The reduced density matrix of the harmonic oscillator system coupled to thermal bath of oscillators is derived for arbitrary spectrum of bath…
Different well-know ways to reheat the universe such as instant preheating, the creation of particles nearly or conformally coupled with gravity, or from the decay products of a curvaton field, are revisited and discussed in detail in the…
During (re)heating of the universe after inflation, the relativistic decay products of the inflaton field $\phi$ must lose energy and additional particles must be produced to attain a thermalised state at a temperature $T_{\reh}$. We…
At the end of inflation, dynamical instability can rapidly deposit the energy of homogeneous cold inflaton into excitations of other fields. This process, known as preheating, is rather violent, inhomogeneous and non-linear, and has to be…
Reheating after inflation occurs due to particle production by the oscillating inflaton field. In this paper we describe the perturbative approach to reheating, and then concentrate on effects beyond the perturbation theory. They are…
The instant preheating mechanism in the framework of a scale invariant two measures theory is studied. We introduce this mechanism into a non oscillating inflationary model as another possible solution to the reheating of the universe in…
We propose a non-oscillatory no-scale supergravity model of inflation (NO-NO inflation) in which the inflaton does not oscillate at the end of the inflationary era. Instead, the Universe is then dominated by the inflaton kinetic energy…
We study inflationary models in which the effective potential of the inflaton field does not have a minimum, but rather gradually decreases at large $\phi$. In such models the inflaton field does not oscillate after inflation, and its…
During cosmological inflation, it has been suggested that fields coupled to the inflaton can be excited by the slow-rolling inflaton into a quasi-stable non-vacuum state. Within this scenario of ``warm inflation'', this could allow for a…