Related papers: The Inflationary Wavefunction and its Initial Cond…
Parametric resonance or preheating is a plausible mechanism for bringing about the transition between the inflationary phase and a hot, radiation dominated universe. This epoch results in the rapid production of heavy particles far from…
Does the observable spectrum of cosmic fluctuations depend on detailed initial conditions? This addresses the question if the general inflationary paradigm is sufficient to predict within a given model the spectrum and amplitude of cosmic…
In this paper we calculate the gravitational-wave power-spectra corresponding to different types of transitions between the inflationary regime and the radiation era. We study four cases, where inflation is followed by a stiff matter phase,…
We use a numerical code to compute the density perturbations generated during an inflationary epoch which includes a spontaneous symmetry breaking phase transition. A sharp step in the inflaton potential generates $k$ dependent oscillations…
We study the two-phase scenario following inflation, where the initial step is preheating, accompanied by a step of perturbative reheating at which inflaton field decays transferring all of its energy to create relativistic particles, the…
We study the Schwinger effect during inflation and its imprints on the primordial power spectrum and bispectrum. The produced charged particles by Schwinger effect during inflation can leave a unique angular dependence on the primordial…
In the primordial universe, fields with mass much larger than the mass-scale of the event-horizon (such as the Hubble parameter in inflation) exist ubiquitously, and can be excited from time to time and oscillate quickly around their…
We investigate the possibility that fields coupled to the inflaton can influence the primordial spectrum of density perturbations through their coherent motion. For example, the second field in hybrid inflation might be oscillating at the…
The sensitivity of inflationary spectra to initial conditions is addressed in the context of a phenomenological model that breaks Lorentz invariance by dissipative effects above some threshold energy $\Lambda$. These effects are obtained…
The post-inflationary evolution of inflation-produced magnetic fields, conventional or not, can change dramatically when two fundamental issues are accounted for. The first is causality, which demands that local physical processes can never…
During inflationary preheating, the energy stored in the inflaton field is rapidly converted into excitations of other entropy fields. This stage is characterized by exponential particle production due to parametric resonance and is…
Fluctuation effects at first order phase transitions driven by changes of other-than-temperature factors like pressure, concentration, or external fields are investigated by perturbation theory. The results for the fluctuation contributions…
A simple inflationary model based on loop quantum cosmology is considered. Within this framework, we show that inflation does not necessarily erase the infor- mation prior to its onset, but that such information may leave its imprint in the…
We consider an inflationary kinetic function with an integrable pole that is traversed during inflation. This scenario leads to enhanced spectra of primordial scalar inhomogeneities with detectable signals: formation of primordial black…
The appearance of peaks in various primordial fluctuation Fourier power spectra is a generic prediction of the inflationary scenario. We investigate whether future experiments, in particular the satellite experiment PLANCK, will be able to…
We report on a novel phenomenon of the resonance effect of primordial density perturbations arisen from a sound speed parameter with an oscillatory behavior, which can generically lead to the formation of primordial black holes in the early…
The possibility of thermally induced initial density perturbations in inflationary cosmology is examined. The fluctuation dynamics of a scalar field plus thermal bath system during slow roll is described by a Langevin-like equation.…
We propose an inflation scenario with three independent stages of cold, warm and thermal inflation, respectively, driven by different scalar fields, motivated by the large number of such fields predicted in most extensions of the Standard…
Inflation in the early Universe is one of the most promising probes of gravity in the high-energy regime. However, observable scales give access to a limited window in the inflationary dynamics. In this essay, we argue that quantum…
The tree order power spectra of primordial inflation depend upon the norm-squared of mode functions which oscillate for early times and then freeze in to constant values. We derive simple differential equations for the power spectra, that…