scholarly journals Hamilton’s approach in cosmological inflation with an exponential potential and its observational constraints

2019 ◽  
Vol 364 (4) ◽  
Author(s):  
Omar E. Núñez ◽  
J. Socorro ◽  
Rafael Hernández-Jiménez
Keyword(s):  
Observational Constraints ◽  
Exponential Potential ◽  
Cosmological Inflation

scholarly journals Induced gravity effect on inflationary parameters in a holographic cosmology

2020 ◽  
Vol 29 (02) ◽  
pp. 2050010 ◽  
Author(s):  
Aatifa Bargach ◽  
Farida Bargach ◽  
Ahmed Errahmani ◽  
Taoufik Ouali
Keyword(s):  
Model Parameters ◽  
Observational Constraints ◽  
Tachyon Field ◽  
Exponential Potential ◽  
Quadratic Potential ◽  
Induced Gravity ◽  
Slow Roll ◽  
Inflationary Parameters ◽  
Correction Terms ◽  
Good Agreement

We investigate the observational constraints on inflationary parameters in the context of a holographic cosmology with an induced gravity correction. We consider two situations where a universe is first filled with a scalar field and second with a tachyon field. Both cases are investigated in a slow-roll regime. We adopt a quadratic potential and an exponential potential for the scalar and the tachyon inflation, respectively. In this regard, the standard background and perturbative parameters characterizing the inflationary era are modified by correction terms. We show a good agreement between theoretical model parameters and Planck2018 observational data for both scalar and tachyon fields.

A SIMPLE QUINTESSENTIAL INFLATION MODEL

2009 ◽  
Vol 24 (08n09) ◽  
pp. 1639-1642 ◽  
Author(s):  
M. C. BENTO ◽  
R. GONZÁLEZ FELIPE ◽  
N. M. C. SANTOS
Keyword(s):  
Scalar Field ◽  
Simple Model ◽  
Parameter Space ◽  
Observational Constraints ◽  
Exponential Potential ◽  
Wide Region ◽  
Present Epoch ◽  
Inflation Model

A simple model of quintessential inflation with the modified exponential potential e-αϕ[A + (ϕ-ϕ0)2] is analyzed in the braneworld context. Considering reheating via instant preheating, the evolution of the scalar field from inflation to the present epoch is consistent with the observational constraints in a wide region of the parameter space.

scholarly journals Reheating in small-field inflation on the brane: the swampland criteria and observational constraints in light of the PLANCK 2018 results

2021 ◽  
Vol 81 (6) ◽  
Author(s):  
Constanza Osses ◽  
Nelson Videla ◽  
Grigoris Panotopoulos
Keyword(s):  
Inflationary Universe ◽  
Observational Constraints ◽  
Small Field ◽  
De Sitter ◽  
Brane Cosmology ◽  
Planck Mass ◽  
Brane Model ◽  
Cosmological Inflation ◽  
Refined Version

AbstractWe study cosmological inflation and its dynamics in the framework of the Randall–Sundrum II brane model. In particular, we analyze in detail four representative small-field inflationary potentials, namely Natural inflation, Hilltop inflation, Higgs-like inflation, and Exponential SUSY inflation, each characterized by two mass scales. We constrain the parameters for which a viable inflationary Universe emerges using the latest PLANCK results. Furthermore, we investigate whether or not those models in brane cosmology are consistent with the recently proposed Swampland Criteria, and give predictions for the duration of reheating as well as for the reheating temperature after inflation. Our results show that (i) the distance conjecture is satisfied, (ii) the de Sitter conjecture and its refined version may be avoided, and (iii) the allowed range for the five-dimensional Planck mass, $$M_5$$ M 5 , is found to be $$10^5\,\text {TeV}\lesssim M_5\lesssim 10^{12}\,\text {TeV}$$ 10 5 TeV ≲ M 5 ≲ 10 12 TeV . Our main findings indicate that non-thermal leptogenesis cannot work within the framework of RS-II brane cosmology, at least for the inflationary potentials considered here.

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.

Observational Constraints on Models of the Solar Background Spectrum

1999 ◽  
Vol 516 (2) ◽  
pp. 939-945 ◽  
Author(s):  
Th. Straus ◽  
G. Severino ◽  
F.‐L. Deubner ◽  
B. Fleck ◽  
S. M. Jefferies ◽  
...  
Keyword(s):  
Observational Constraints ◽  
Background Spectrum

A Realistic Grid of Models for the Gravitationally Lensed Einstein Cross (Q2237+0305) and Its Relation to Observational Constraints

1998 ◽  
Vol 495 (2) ◽  
pp. 609-616 ◽  
Author(s):  
Kyu‐Hyun Chae ◽  
David A. Turnshek ◽  
Valery K. Khersonsky
Keyword(s):  
Observational Constraints

scholarly journals Magnetospheric Structure of Rotation-Powered Neutron Stars

1992 ◽  
Vol 128 ◽  
pp. 56-77 ◽  
Author(s):  
Jonathan Arons
Keyword(s):  
Radio Emission ◽  
Gamma Radiation ◽  
Heavy Ions ◽  
Theoretical Work ◽  
Future Research ◽  
Observational Constraints ◽  
Polar Caps ◽  
Recent Theoretical Work ◽  
Density Flow ◽  
Promising Avenue

AbstractI survey recent theoretical work on the structure of the magnetospheres of rotation-powered pulsars, within the observational constraints set by their observed spindown, their ability to power synchrotron nebulae and their ability to produce beamed collective radio emission, while putting only a small fraction of their energy into incoherent X- and gamma radiation. I find no single theory has yet given a consistent description of the magnetosphere, but I conclude that models based on a dense outflow of pairs from the polar caps, permeated by a lower density flow of heavy ions, are the most promising avenue for future research.

scholarly journals Can the Local Bubble explain the radio background?

2021 ◽  
Vol 502 (2) ◽  
pp. 2807-2814
Author(s):  
Martin G H Krause ◽  
Martin J Hardcastle
Keyword(s):  
Magnetic Field ◽  
Energy Density ◽  
Radio Emission ◽  
Magnetic Energy ◽  
Cosmic Ray ◽  
Observational Constraints ◽  
Local Bubble ◽  
Magnetic Energy Density ◽  
Magnetic Field Model ◽  
Radio Background

ABSTRACT The ARCADE 2 balloon bolometer along with a number of other instruments have detected what appears to be a radio synchrotron background at frequencies below about 3 GHz. Neither extragalactic radio sources nor diffuse Galactic emission can currently account for this finding. We use the locally measured cosmic ray electron population, demodulated for effects of the Solar wind, and other observational constraints combined with a turbulent magnetic field model to predict the radio synchrotron emission for the Local Bubble. We find that the spectral index of the modelled radio emission is roughly consistent with the radio background. Our model can approximately reproduce the observed antenna temperatures for a mean magnetic field strength B between 3 and 5 nT. We argue that this would not violate observational constraints from pulsar measurements. However, the curvature in the predicted spectrum would mean that other, so far unknown sources would have to contribute below 100 MHz. Also, the magnetic energy density would then dominate over thermal and cosmic ray electron energy density, likely causing an inverse magnetic cascade with large variations of the radio emission in different sky directions as well as high polarization. We argue that this disagrees with several observations and thus that the magnetic field is probably much lower, quite possibly limited by equipartition with the energy density in relativistic or thermal particles (B = 0.2−0.6 nT). In the latter case, we predict a contribution of the Local Bubble to the unexplained radio background at most at the per cent level.

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