Related papers: Gravitational inflaton decay and the hierarchy pro…
We study the problem of scalar particle production after inflation by a rapidly oscillating inflaton field. We use the framework of the chaotic inflation scenario with quartic and quadratic inflaton potentials. Particular attention is paid…
We point out that the inflaton inevitably couples to all non-conformally coupled matters gravitationally through an oscillation in the Hubble parameter or the cosmic scale factor. It leads to particle production during the inflaton…
We study perturbative reheating at the end of fibre inflation where the inflaton is a closed string modulus with a Starobinsky-like potential. We first derive the spectral index $n_s$ and the tensor-to-scalar ratio $r$ as a function of the…
Despite having important cosmological implications, the reheating phase is believed to play a crucial role in cosmology and particle physics model building. Conventionally, the model of reheating with an arbitrary coupling of inflaton to…
The success of primordial nucleosynthesis imposes stringent bounds on the abundance of gravitational relics. This is particularly true for gravitinos, which - for models with gravitationally mediated supersymmetry breaking - are expected to…
We show that the gravitino-overproduction problem is prevalent among inflation models in supergravity. An inflaton field generically acquires (effective) non-vanishing auxiliary field, if the Kahler potential is non-minimal. The inflaton…
In this paper a quantum N = 4 super Yang-Mills theory perturbed by dilaton-coupled scalars, is considered. The induced effective action for such a theory is calculated on a dilaton-gravitational background using the conformal anomaly found…
Gravitinos are a fundamental prediction of supergravity, their mass ($m_{G}$) is informative of the value of the SUSY breaking scale, and, if produced during reheating, their number density is a function of the reheating temperature…
The physics of the inflationary universe requires the study of the out of equilibrium evolution of quantum fields in curved spacetime. We present the evolution for both the geometry and the matter (described by the quantum inflaton field)…
We study in detail (p)reheating after multi-field inflation models with a particular focus on N-flation. We consider a variety of different couplings between the inflatons and the matter sector, including both quartic and trilinear…
We use gauge/gravity correspondence to study the gravitational reheating of strongly coupled gauge theories in the rapid exit from the long inflationary (de Sitter) phase. We estimate the maximal reheating temperature of holographic models…
We discuss the way of solving the hierarchy problem. We show that starting at the Planck scale, the three energy scales -- inflationary, electroweak and the cosmological ones can be restored. The formation of small parameters is proposed…
We investigate the gravitational production of a scalar field $\chi$ with a mass exceeding the Hubble scale during inflation $m_\chi \gtrsim H_I$, employing both analytical and numerical approaches. We demonstrate that the steepest descent…
Grand unified theories may display multiply interacting fields with strong coupling dynamics. This poses two new problems: (1) What is the nature of chaotic reheating after inflation, and (2) How is reheating sensitive to the mass spectrum…
We study preheating in plateau inflation in the Palatini formulation of general relativity, in a special case that resembles Higgs inflation. It was previously shown that the oscillating inflaton field returns to the plateau repeatedly in…
We investigate the stochastic gravitational wave (GW) spectrum resulting from graviton bremsstrahlung during inflationary reheating. We focus on an inflaton $\phi$ oscillating around a generic monomial potential $V(\phi) \propto \phi^n$,…
It is shown that a positive non-minimal coupling of the Higgs field to gravity can solve the two problems in inflation models in which postinflationary universe is dominated by an energy with stiff equation of state such as a kination,…
We argue that the fine tuning problems of scalar-driven inflation may be worse than is commonly believed. The reason is that reheating requires the inflaton to be coupled to other matter fields whose vacuum fluctuations alter the inflaton…
In a recent work, we demonstrated that a modified gravity model in which a scalar "darkon" field is coupled to both the standard Riemannian metric and to another non-Riemannian volume form is compatible with observational data from…
We discuss inflaton decays and reheating in no-scale Starobinsky-like models of inflation, calculating the effective equation-of-state parameter, $w$, during the epoch of inflaton decay, the reheating temperature, $T_{\rm reh}$, and the…