相关论文: States of Low Energy in bouncing inflationary scen…
We show that it is possible to combine an early phase of String Gas Cosmology which can explain the origin of the observed structures on cosmological scales with a short later period of power law inflation which creates spatial flatness.…
The global dynamics of a homogeneous universe in Loop Quantum Cosmology is viewed as a scattering process of its geometrodynamical equivalent. This picture is applied to build a flexible (easy to generalize) and not restricted just to…
Inflation is a necessary cosmic mechanism to cure basic inconsistencies of the standard model of cosmology. These problems are usually `fixed' by postulating the existence of a scalar field (called the ``inflaton''). However, other less ad…
This work is an analytical study of the main differences between classical inflationary effects of a fast-roll regime and imprints of hybrid Loop Quantum Cosmology (LQC) on the primordial power spectrum. Effective LQC solutions of…
Loop quantum cosmology is considered in inflation era. A slow roll scalar field solution with power law potential is presented in the neighborhood of transition time, i.e. when the universe enters inflation phase from super-inflation. The…
In cosmology, phenomenologically motivated expressions for running vacuum are commonly parametrized as linear functions $\Lambda(H^2)$ or $\Lambda(R)$. Such kind of models assume an equation of state for vacuum given by $\,\overline…
In this letter, we stress that the simplest cosmological model consisting in a massless scalar field minimally coupled to homogeneous and isotropic gravity has an in-built $\SL(2,\mathbb{R})$ symmetry. Protecting this symmetry naturally…
We study the effect on the primordial tensor power spectrum of varying the number of e-folds during slow-roll inflation in Loop Quantum Cosmology with a Starobinsky potential. Using the hybrid quantization approach, we derive the effective…
In this article, we investigated a Locally Rotationally Symmetric (LRS) Bianchi-II cosmological model with matter and Holographic Dark Energy (HDE) in the context of $f(R)$ theory of gravity. In order to find exact solutions to the field…
In this Thesis we will explicitly construct Hadamard states with different features. In the two first cases, the states will be constructed in static and in cosmological spacetimes. In one of the cases, the states will be constructed in…
Standard cosmology poses a number of important questions. Apart from its singular origin, it possesses early and late accelerating phases required to account for observations. The vacuum energy has been considered as a possible way to…
Inflation, a period of exponential expansion in the early Universe, is considered an important part of the standard $\Lambda$CDM cosmological model, and plays a crucial role in explaining a wide range of current observations. The standard…
We use broadband photometry extending from the rest-frame UV to the near-IR to fit the individual spectral energy distributions (SEDs) of 63 bright (L(Ly-alpha) > 10^43 ergs/s) Ly-alpha emitting galaxies (LAEs) in the redshift range 1.9 < z…
Within the framework of inflationary models that incorporate a spontaneous reduction of the wave function for the emergence of the seeds of cosmic structure, we study the effects on the primordial scalar power spectrum by choosing a novel…
We construct and discuss Hadamard states for both scalar and Dirac spinor fields in a large class of spatially flat Friedmann-Robertson-Walker spacetimes characterised by an initial phase either of exponential or of power-law expansion. The…
We do not observe quantum effects on cosmological scales. Thus, if loop quantum cosmology (LQC) is to provide an accurate depiction of the real world, it must allow for quantum states of spacetime geometry which are semi-classical in two…
There is growing experimental and theoretical evidence that very clean two dimensional electron systems form unidirectional charge density waves (UCDW) or ``striped'' states at low temperatures and at Landau level filling fractions of the…
Atomic ionization by intense mid-infrared (mid-IR) pulses produces low electron energy features that the strong-field approximation, which is expected to be valid in the tunneling ionization regime characterized by small Keldysh parameters…
In the standard inflationary paradigm, cosmological density perturbations are generated as quantum fluctuations in the early Universe, but then undergo a quantum-to-classical transition. A key role in this transition is played by squeezing…
We introduce a class of states characterized by proposed conditions of homogeneity and isotropy in loop quantum gravity and construct concrete examples given by Bell-network states on a special class of homogeneous graphs. Such states…