Related papers: Disorder in the Early Universe
In inflationary cosmology, the particles constituting the Universe are created after inflation in the process of reheating due to the interaction with the oscillating inflaton field. We briefly review the basics of the slow reheating, and…
We review the theory of inflationary perturbations. Perturbations at both linear and nonlinear orders are reviewed. We also review a variety of inflation models, emphasizing their signatures on cosmic perturbations.
After introducing gauge-invariant cosmological perturbation theory we give an improved set of governing equations for multiple fluids including energy transfer. Having defined adiabatic and entropic perturbations we derive the…
It is commonly believed that our Universe has experienced two different stages of accelerated expansion. The early stage is known as inflation and the current acceleration is driven by dark energy. Observing inflation and dark energy…
We revisit the study of the phenomenology associated to a burst of particle production of a field whose mass is controlled by the inflaton field and vanishes at one given instance during inflation. This generates a bump in the correlators…
The standard big bang cosmological model and the history of the early universe according to the grand unified theories of strong, weak and electromagnetic interactions are summarized. The shortcomings of big bang are discussed together with…
The pre-big bang scenario describes the evolution of the Universe from an initial state approaching the flat, cold, empty, string perturbative vacuum. The choice of such an initial state is suggested by the present state of our Universe if…
We propose an intuitive framework for studying the problem of initial conditions in slow-roll inflation. In particular, we consider a universe at high, but sub-Planckian energy density and analyze the circumstances under which it is…
The notion of inflation (past or present) in standard cosmological models is shown to be a consequence of a sufficiently high second law entropy production from the internal heating of the universal expansion. The longitudinal viscous…
We study the early-stage kinetics of thermodynamically unstable systems with quenched disorder. We show analytically that the growth of initial fluctuations is amplified by the presence of disorder. This is confirmed by numerical…
After cosmic inflation and before the transition to radiation domination, the cosmic energy density may have been dominated during an extended period by an oscillating massive scalar condensate. We show that during this period, sub-Hubble…
Higher-form flux that extends in all 3+1 dimensions of spacetime is a source of positive vacuum energy that can drive meta-stable eternal inflation. If the flux also threads compact extra dimensions, the spontaneous nucleation of a bubble…
Inflation can act as a space-time microscope for Planck or string scale effects, leaving potentially observable traces in the primordial perturbation spectrum. I discuss two frameworks that were used recently to study this phenomenon:…
Oscillons are massive, long-lived, localized excitations of a scalar field. We show that in a large class of well-motivated single-field models, inflation is followed by self-resonance, leading to copious oscillon generation and a lengthy…
In simple inflationary cosmological scenarios the near-exponential growth can be followed by a long period in which the Universe is dominated by the oscillating inflaton condensate. The condensate is initially almost homogeneous, but…
If you fall into a real astronomical black hole (choosing a supermassive black hole, to make sure that the tidal forces don't get you first), then you will probably meet your fate not at a central singularity, but rather in the…
Over the past three years we have determined the basic features of our Universe. It is spatially flat; accelerating; comprised of 1/3 a new form of matter, 2/3 a new form of energy, with some ordinary matter and a dash of massive neutrinos;…
This note makes a self-contained exposition of the basic facts of big bang cosmology as they relate to inflation. The fundamental problems with that model are then explored. A quartic scalar potential model of inflation is evaluated which…
We show that in the simplest theories of spontaneous symmetry breaking one can have a stage of a fast-roll inflation. In this regime the standard slow-roll condition |m^2| << H^2 is violated. Nevertheless, this stage can be rather long if…
We demonstrate the existence of chaos in realistic models of two-field inflation. The chaotic motion takes place after the end of inflation, when the fields are free to oscillate and their motion is only lightly damped by the expansion of…