Related papers: High frequency oscillations of Newton's constant i…
We consider the classical fluctuations of the gravitational constant generated by bubbles in the inflationary universe. For extended inflation, we demonstrate numerically how and how large fluctuations are produced during bubble expansion.…
In this paper the effects of time-dependent Newton constant G during inflation are studied. We present the formalism of curvature perturbations in an inflationary system with a time-dependent Newton constant. As an example we consider a toy…
According to the Brans--Dicke theory, the value of the gravitational constant G which we measure at present is determined by the value of the Brans--Dicke scalar field \phi at the end of inflation. However, due to quantum fluctuations of…
Spectrum of density perturbations in the Universe generated from quantum-gravitational fluctuations in slow-roll-over inflationary scenarios with the Brans-Dicke gravity is calculated. It is shown that after inflation the isocurvature mode…
We draw attention to the possibility that inflation (i.e. accelerated expansion) might continue after the end of slow roll, during a period of fast oscillations of the inflaton field \phi . This phenomenon takes place when a mild…
Quantum fluctuations of scalar fields during inflation could determine the very large-scale structure of the universe. In the case of general scalar-tensor gravity theories these fluctuations lead to the diffusion of fundamental constants…
Variation of constants in the very early universe can generate inflation. We consider a scenario where the strong coupling constant was changing in time and where the gluon condensate underwent a phase transition ending the inflation.
It is widely accepted that the primordial universe experienced a brief period of accelerated expansion called inflation. This scenario provides a plausible solution to the horizon and flatness problems. However, the particle physics…
The mechanism for triggering the universe inflation could be that at very early periods the time variable was discrete instead of smooth. Alternatively, and perhaps equivalently, it could be the consequence that the metrics of the early…
We derive a theoretical upper bound on the oscillation frequency in the scalar perturbation power spectrum of single-field inflation. Oscillations are most naturally produced by modified vacua with varying phase. When this phase changes…
The Higgs field is an attractive candidate for the inflaton because it is an observationally confirmed fundamental scalar field. Importantly, it can be modeled by the most general renormalizable scalar potential. However, if the classical…
Quantum gravitational back-reaction offers the potential of simultaneously resolving the problem of the cosmological constant and providing a natural model of inflation in which scalars play no special role. In this model inflation begins…
In double-field inflation, which exploits two scalar fields, one of the fields rolls slowly during inflation whereas the other field is trapped in a meta-stable vacuum. The nucleation rate from the false vacuum to the true one becomes…
We employ the formalism of the effective field theory of inflation to study the effects of a sudden change in the speed of sound of the inflationary perturbations. Such an event generates a feature with high frequency oscillations both in…
In this paper, we study the dynamics of the Chern-Simons Inflation Model proposed by Alexander, Marciano and Spergel. According to this model, inflation begins when a fermion current interacts with a turbulent gauge field in a space larger…
A remarkable prediction of the Standard Model is that, in the absence of corrections lifting the energy density, the Higgs potential becomes negative at large field values. If the Higgs field samples this part of the potential during…
In Brans-Dicke theory the Universe becomes divided after inflation into many exponentially large domains with different values of the effective gravitational constant. Such a process can be described by diffusion equations for the…
During or towards the end of inflation, the Standard Model (SM) Higgs forms a condensate with a large amplitude. Following inflation, the condensate oscillates, decaying non-perturbatively into the rest of the SM species. The resulting…
The impact of particle production during inflation on the primordial curvature perturbation spectrum is investigated both analytically and numerically. We obtain an oscillatory behavior on small scales, while on large scales the spectrum is…
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…