Quintessential inflation with αattractors
Abstract
A novel approach to quintessential inflation model building is studied, within the framework of αattractors, motivated by supergravity theories. Inflationary observables are in excellent agreement with the latest CMB observations, while quintessence explains the dark energy observations without any finetuning. The model is kept intentionally minimal, avoiding the introduction of many degrees of freedom, couplings and mass scales. In stark contrast to ΛCDM, for natural values of the parameters, the model attains transient accelerated expansion, which avoids the future horizon problem, while it maintains the field displacement mildly subPlanckian such that the flatness of the quintessential tail is not lifted by radiative corrections and violations of the equivalence principle (fifth force) are under control. In particular, the required value of the cosmological constant is near the eletroweak scale. Attention is paid to the reheating of the Universe, which avoids gravitino overproduction and respects nucleosynthesis constraints. Kination is treated in a model independent way. A spike in gravitational waves, due to kination, is found not to disturb nucleosynthesis as well.
 Authors:
 Consortium for Fundamental Physics, Physics Department, Lancaster University, Lancaster LA1 4YB (United Kingdom)
 Publication Date:
 OSTI Identifier:
 22676158
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2017; Journal Issue: 06; Other Information: Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ATTRACTORS; COMPUTERIZED SIMULATION; COSMOLOGICAL CONSTANT; COUPLING; DEGREES OF FREEDOM; EQUIVALENCE PRINCIPLE; EXPANSION; GRAVITATIONAL WAVES; GRAVITINOS; MASS; NONLUMINOUS MATTER; NUCLEOSYNTHESIS; RADIATIVE CORRECTIONS; RELICT RADIATION; SUPERGRAVITY; TRANSIENTS; UNIVERSE
Citation Formats
Dimopoulos, Konstantinos, and Owen, Charlotte, Email: k.dimopoulos1@lancaster.ac.uk, Email: c.owen@lancaster.ac.uk. Quintessential inflation with αattractors. United States: N. p., 2017.
Web. doi:10.1088/14757516/2017/06/027.
Dimopoulos, Konstantinos, & Owen, Charlotte, Email: k.dimopoulos1@lancaster.ac.uk, Email: c.owen@lancaster.ac.uk. Quintessential inflation with αattractors. United States. doi:10.1088/14757516/2017/06/027.
Dimopoulos, Konstantinos, and Owen, Charlotte, Email: k.dimopoulos1@lancaster.ac.uk, Email: c.owen@lancaster.ac.uk. Thu .
"Quintessential inflation with αattractors". United States.
doi:10.1088/14757516/2017/06/027.
@article{osti_22676158,
title = {Quintessential inflation with αattractors},
author = {Dimopoulos, Konstantinos and Owen, Charlotte, Email: k.dimopoulos1@lancaster.ac.uk, Email: c.owen@lancaster.ac.uk},
abstractNote = {A novel approach to quintessential inflation model building is studied, within the framework of αattractors, motivated by supergravity theories. Inflationary observables are in excellent agreement with the latest CMB observations, while quintessence explains the dark energy observations without any finetuning. The model is kept intentionally minimal, avoiding the introduction of many degrees of freedom, couplings and mass scales. In stark contrast to ΛCDM, for natural values of the parameters, the model attains transient accelerated expansion, which avoids the future horizon problem, while it maintains the field displacement mildly subPlanckian such that the flatness of the quintessential tail is not lifted by radiative corrections and violations of the equivalence principle (fifth force) are under control. In particular, the required value of the cosmological constant is near the eletroweak scale. Attention is paid to the reheating of the Universe, which avoids gravitino overproduction and respects nucleosynthesis constraints. Kination is treated in a model independent way. A spike in gravitational waves, due to kination, is found not to disturb nucleosynthesis as well.},
doi = {10.1088/14757516/2017/06/027},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 06,
volume = 2017,
place = {United States},
year = {Thu Jun 01 00:00:00 EDT 2017},
month = {Thu Jun 01 00:00:00 EDT 2017}
}

Sneutrino inflation employs the fermionic partners of the inflaton and stabilizer field as righthanded neutrinos to realize the seesaw mechanism for light neutrino masses. We show that one can improve the latest version of this scenario and its consistency with the Planck data by embedding it in the theory of cosmological αattractors.

Cosmic microwave background and largescale structure constraints on a simple quintessential inflation model
We derive constraints on a simple quintessential inflation model, based on a spontaneously broken {Phi}{sup 4} theory, imposed by the Wilkinson Microwave Anisotropy Probe threeyear data (WMAP3) and by galaxy clustering results from the Sloan Digital Sky Survey (SDSS). We find that the scale of symmetry breaking must be larger than about 3 Planck masses in order for inflation to generate acceptable values of the scalar spectral index and of the tensortoscalar ratio. We also show that the resulting quintessence equationofstate can evolve rapidly at recent times and hence can potentially be distinguished from a simple cosmological constant in thismore » 
Quintessential inflation on the brane and the relic gravity wave background
Quintessential inflation describes a scenario in which both inflation and dark energy (quintessence) are described by the same scalar field. In conventional braneworld models of quintessential inflation gravitational particleproduction is used to reheat the universe. This reheating mechanism is very inefficient and results in an excessive production of gravity waves which violate nucleosynthesis constraints and invalidate the model. We describe a new method of realizing quintessential inflation on the brane in which inflation is followed by 'instant preheating' (Felder, Kofman and Linde 1999). The larger reheating temperature in this model results in a smaller amplitude of relic gravity waves whichmore » 
Tachyonic quintessential inflation
I study the possibility of constructing an observationally viable scenario where both early inflation and the recently detected accelerated expansion of the universe can be explained by using a single scalar field associated with the tachyon. The reheating phase becomes crucial in enabling us to have a consistent cosmology and also to get a second accelerated expansion period. A discussion using an exponential potential is presented. 
Cosmic microwave background and largescale structure constraints on a simple quintessential inflation model
We derive constraints on a simple quintessential inflation model, based on a spontaneously broken {phi}{sup 4} theory, imposed by the Wilkinson Microwave Anisotropy Probe threeyear data (WMAP3) and by galaxy clustering results from the Sloan Digital Sky Survey (SDSS). We find that the scale of symmetry breaking must be larger than about 3 Planck masses in order for inflation to generate acceptable values of the scalar spectral index and of the tensortoscalar ratio. We also show that the resulting quintessence equation of state can evolve rapidly at recent times and hence can potentially be distinguished from a simple cosmological constantmore »