Related papers: The Quantum Gravitational Back-Reaction On Inflati…
We calculate the covariant one-loop quantum gravitational effective action for a scalar field model inspired by the recently proposed nonminimal natural inflation model. Our calculation is perturbative, in the sense that the effective…
We investigate the effects of the generalized uncertainty principle on the inflationary dynamics of the early universe in both standard and braneworld viewpoint. We choose the Randall-Sundrum II model as our underlying braneworld scenario.…
The leading quantum correction to the power spectrum of a gravitationally-coupled light scalar field is calculated, assuming that it is generated during a phase of single-field, slow-roll inflation.
In the very early Universe matter can be described as a conformal invariant ultra-relativistic perfect fluid, which does not contribute, on classical level, to the evolution of the isotropic and homogeneous metric. However, in this…
We obtain effective equations of inflationary dynamics for the mean inflaton and metric fields in the no-boundary and tunneling quantum states of the Universe. In the slow roll approximation (taking the form of the local Schwiger-DeWitt…
Inflationary cosmology proposes that the early Universe undergoes accelerated expansion, driven, in simple scenarios, by a single scalar field, or inflaton. The form of the inflaton potential determines the initial spectra of density…
The spectrum of the gravitational wave background originating from quantum fluctuations during inflation is calculated numerically for various inflation models over a wide range of frequencies. We take into account four ingredients : the…
We study in detail the power spectra of scalar and tensor perturbations generated during inflation in loop quantum cosmology (LQC). After clarifying in a novel quantitative way how inverse-volume corrections arise in inhomogeneous settings,…
This paper focuses on the search for a coherent and consistent formulation to describe quantum gravity corrections to Quantum Field Theory. We implement two fundamental ingredients discussed in previous analyses: on one hand, the…
We present a quantum quadratic gravity inflationary scenario that can accommodate the new cosmological constraints, which have disfavored Starobinsky inflation. The theory is asymptotically free in the ultraviolet, but 1-loop running is…
We calculate the full spectrum, as observed today, of the cosmological gravitational waves generated within a model based on loop quantum cosmology. It is assumed that the universe, after the transition to the classical regime, undergoes a…
We dig into the semi-classical description of gravity by studying one-loop corrections to primordial power spectra generated during cosmic inflation from gravitational nonlinear interactions. In the realm of the Effective Field Theory (EFT)…
Cosmic Inflation provides an attractive framework for understanding the early universe and the cosmic microwave background. It can readily involve energies close to the scale at which Quantum Gravity effects become important. General…
Loop Quantum Gravity (L.Q.G.) is one of the two most promising tentative theory for a quantum description of gravity. When applied to the entire universe, the so-called Loop Quantum Cosmology (L.Q.C.) framework offers microscopical models…
In bounce inflation scenario, the inflation is singularity-free, while the advantages of inflation are reserved. We analytically calculate the power spectrum of its primordial gravitational waves (GWs), and show a universal result including…
We obtain the effective inflaton potential during slow roll inflation by including the one loop quantum corrections to the energy momentum tensor from scalar curvature and tensor perturbations as well as quantum fluctuations from light…
The primordial spectrum of fluctuations may present a large peak as a result of enhancing features during inflation. This may include, but is not limited to, bumps in the inflaton's potential, phases of ultra-slow-roll or turns in…
We consider the stochastic gravitational wave background induced by arbitrary source fields that are amplified during cosmological inflation. The associated tensor spectral index is shown to be given, under minimal assumptions, by a simple…
The primordial spectrum of cosmological tensor perturbations is considered as a possible probe of quantum gravity effects. Together with string theory, loop quantum gravity is one of the most promising frameworks to study quantum effects in…
We examine the quantum loop effects on the single-field inflationary models in a spatially flat Friedmann-Robertson-Walker (FRW) cosmological space-time with a general self-interacting scalar field potential, which is modeled in terms of…