scholarly journals Dynamics of cosmological inflation and predictions for reheating in the light of 2018 PLANCK results

2021 ◽  
Vol 136 (4) ◽  
Author(s):  
Grigoris Panotopoulos ◽  
Matías López ◽  
Nelson Videla
Keyword(s):  
Cosmological Inflation

Q & A. Lisa Randall. [interview]

2019 ◽  
Author(s):  
Adib Rifqi Setiawan
Keyword(s):  
New York ◽  
New York City ◽  
Particle Physics ◽  
Harvard University ◽  
The Past ◽  
Talent Search ◽  
Cosmological Inflation ◽  
On Line ◽  
Theoretical Physicist ◽  
Fundamental Forces

Lisa Randall is a theoretical physicist working in particle physics and cosmology. She was born in Queens, New York City, on June 18, 1962. Lisa Randall is an alumna of Hampshire College Summer Studies in Mathematics; and she graduated from Stuyvesant High School in 1980. She won first place in the 1980 Westinghouse Science Talent Search at the age of 18; and at Harvard University, Lisa Randall earned both a BA in physics (1983) and a PhD in theoretical particle physics (1987) under advisor Howard Mason Georgi III, a theoretical physicist. She is currently Frank B. Baird, Jr. Professor of Science on the physics faculty of Harvard University, where he has been for the past a decade. Her works concerns elementary particles and fundamental forces, and has involved the study of a wide variety of models, the most recent involving dimensions. She has also worked on supersymmetry, Standard Model observables, cosmological inflation, baryogenesis, grand unified theories, and general relativity. Consequently, her studies have made her among the most cited and influential theoretical physicists and she has received numerous awards and honors for her scientific endeavors. Since December 27, 2010 at 00:42 (GMT+7), Lisa Randall is Twitter’s user with account @lirarandall. “Thanks to new followers. Interesting how different it feels broadcasting on line vs.via book or article. Explanations? Pithiness? Rapidity?” is her first tweet.

Cosmological inflation in f(X) gravity theory

2019 ◽  
Vol 26 ◽  
pp. 100401 ◽  
Author(s):  
Hafiza Rizwana Kausar ◽  
Rabia Saleem ◽  
Amara Ilyas
Keyword(s):  
Gravity Theory ◽  
Cosmological Inflation

scholarly journals Exploring the parameter space of modified supergravity for double inflation and primordial black hole formation

2021 ◽  
Author(s):  
Ryotaro Ishikawa ◽  
Sergei V Ketov
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Power Spectrum ◽  
Parameter Space ◽  
Background Radiation ◽  
Fine Tuning ◽  
Primordial Black Hole ◽  
Peak Enhancement ◽  
Microwave Background Radiation ◽  
Cosmological Inflation

Abstract We study the parameter space of the effective (with two scalars) models of cosmological inflation and primordial black hole (PBH) formation in the modified (R+ R 2) supergravity. Our models describe double inflation, whose first stage is driven by Starobinsky’s scalaron coming from the R 2 gravity, and whose second stage is driven by another scalar belonging to the supergravity multiplet. The ultra-slow-roll regime between the two stages leads a large peak (enhancement) in the power spectrum of scalar perturbations, which results in efficient PBH formation. Both inflation and PBH formation are generic in our models, while those PBH can account for a significant part or the whole of dark matter. Some of the earlier proposed models in the same class are in tension (over 3σ) with the observed value of the scalar tilt ns , so that we study more general models with more parameters, and investigate the dependence of the cosmological tilts (ns,r) and the scalar power spectrum enhancement upon the parameters. The PBH masses and their density fraction (as part of dark matter) are also calculated. A good agreement (between 2σ and 3σ) with the observed value of ns requires fine tuning of the parameters, and it is only realized in the so-called δ-models. Our models offer the (super)gravitational origin of inflation, PBH and dark matter together, and may be confirmed or falsified by future precision measurements of the cosmic microwave background radiation and PBH-induced gravitational waves.

scholarly journals Building models of inflation in no-scale supergravity

2020 ◽  
pp. 2030011
Author(s):  
John Ellis ◽  
Marcos A. G. García ◽  
Natsumi Nagata ◽  
Dimitri V. Nanopoulos ◽  
Keith A. Olive ◽  
...  
Keyword(s):  
Cold Dark Matter ◽  
Planck Scale ◽  
Neutrino Masses ◽  
De Sitter ◽  
Building Models ◽  
Scale Models ◽  
Cosmological Inflation ◽  
Text Model ◽  
Hilbert Action ◽  
Scalar Perturbations

After reviewing the motivations for cosmological inflation formulated in the formalism of supersymmetry, we argue that the appropriate framework is that of no-scale supergravity. We then show how to construct within this framework inflationary models whose predictions for the tilt in the spectrum of scalar perturbations, [Formula: see text], and the ratio, [Formula: see text], of tensor and scalar perturbations coincide with those of the [Formula: see text] model of inflation proposed by Starobinsky. A more detailed study of no-scale supergravity reveals a structure that is closely related to that of [Formula: see text] modifications of the minimal Einstein–Hilbert action for general relativity, opening avenues for constructing no-scale de Sitter and anti-de Sitter models by combining pairs of Minkowski models, as well as generalizations of the original no-scale Starobinsky models of inflation. We then discuss the phenomenology of no-scale models of inflation, including inflaton decay and reheating, and then the construction of explicit scenarios based on SU(5), SO(10) and string-motivated flipped SU(5)×U(1) GUT models. The latter provides a possible model of almost everything below the Planck scale, including neutrino masses and oscillations, the cosmological baryon asymmetry and cold dark matter, as well as [Formula: see text] and [Formula: see text].

scholarly journals Inflation with explicit parametric connection between general relativity and scalar–tensor gravity

2018 ◽  
Vol 33 (28) ◽  
pp. 1850161 ◽  
Author(s):  
I. V. Fomin ◽  
S. V. Chervon
Keyword(s):  
General Relativity ◽  
Scale Factor ◽  
Cosmological Inflation ◽  
The Difference ◽  
The Universe

We consider the cosmological inflation with scalar–tensor gravity and compare it with standard inflation based on General Relativity. The difference is determined by the value of the parameter [Formula: see text]. This approach is associated with using the special ansatz which links a function that defines a type of gravity with a scale factor of the universe.

Polymer quantization effects on gauge-flation

2018 ◽  
Vol 15 (10) ◽  
pp. 1850169
Author(s):  
M. Mardaani ◽  
K. Nozari
Keyword(s):  
Hilbert Space ◽  
Quantum Mechanics ◽  
Quantum Gravity ◽  
Gauge Field ◽  
Quantum Cosmology ◽  
Loop Quantum Gravity ◽  
Loop Quantum Cosmology ◽  
Abelian Gauge ◽  
Friedmann Equations ◽  
Cosmological Inflation

Polymer quantum mechanics, as a non-standard representation of quantum mechanics, is based on a symmetric sector of loop quantum gravity known as loop quantum cosmology. In this work, by analyzing the Hamiltonian and Friedmann equations in the standard Hilbert space and polymer Hilbert space, we show that polymer quantization is a successful formalism for a non-Abelian gauge field driving the cosmological inflation, the so-called gauge-flation, in order to remove initial singularity and also keeping the inflationary trajectories in this model as attractors of dynamics after the bounce.

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