scholarly journals Fine-tuning of the initial conditions for hybrid inflation

1998 ◽  
Vol 57 (10) ◽  
pp. 5997-6002 ◽  
Author(s):  
N. Tetradis
Keyword(s):  
Initial Conditions ◽  
Fine Tuning ◽  
Hybrid Inflation

scholarly journals Anamorphosis in hybrid inflation: How to avoid fine-tuning of initial conditions?

2010 ◽  
Author(s):  
Sébastien Clesse ◽  
Jean-Michel Alimi ◽  
André Fuözfa
Keyword(s):  
Initial Conditions ◽  
Fine Tuning ◽  
Hybrid Inflation

scholarly journals Harmonic hybrid inflation

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Federico Carta ◽  
Nicole Righi ◽  
Yvette Welling ◽  
Alexander Westphal
Keyword(s):  
Domain Wall ◽  
Symmetry Breaking ◽  
Initial Conditions ◽  
Scalar Potential ◽  
Field Range ◽  
Slow Roll ◽  
Minimal Form ◽  
Wide Range ◽  
Hybrid Inflation ◽  
Type Iib String Theory

Abstract We present a mechanism for realizing hybrid inflation using two axion fields with a purely non-perturbatively generated scalar potential. The structure of the scalar potential is highly constrained by the discrete shift symmetries of the axions. We show that harmonic hybrid inflation generates observationally viable slow-roll inflation for a wide range of initial conditions. This is possible while accommodating certain UV arguments favoring constraints f ≲ MP and ∆ϕ60 ≲ MP on the axion periodicity and slow-roll field range, respectively. We discuss controlled ℤ2-symmetry breaking of the adjacent axion vacua as a means of avoiding cosmological domain wall problems. Including a minimal form of ℤ2-symmetry breaking into the minimally tuned setup leads to a prediction of primordial tensor modes with the tensor-to-scalar ratio in the range 10−4 ≲ r ≲ 0.01, directly accessible to upcoming CMB observations. Finally, we outline several avenues towards realizing harmonic hybrid inflation in type IIB string theory.

scholarly journals Initial conditions for smooth hybrid inflation

1996 ◽  
Vol 54 (2) ◽  
pp. 1369-1373 ◽  
Author(s):  
G. Lazarides ◽  
C. Panagiotakopoulos ◽  
N. D. Vlachos
Keyword(s):  
Initial Conditions ◽  
Hybrid Inflation

scholarly journals Axion hilltops, Kahler modulus quintessence and the swampland criteria

2019 ◽  
Vol 34 (28) ◽  
pp. 1950164 ◽  
Author(s):  
Maxim Emelin ◽  
Radu Tatar
Keyword(s):  
Degrees Of Freedom ◽  
Initial Conditions ◽  
Effective Field ◽  
Fine Tuning ◽  
De Sitter ◽  
Moduli Stabilization ◽  
Nonperturbative Effect ◽  
Initial Conditions Problem ◽  
Field Excursion ◽  
Hubble Time

We study the interplay among extrema of axion potentials, Kahler moduli stabilization and the swampland criteria. We argue that moving away from the minima of nonperturbatively generated axion potentials can lead to a runaway behavior of moduli that govern the couplings in the effective field theory. The proper inclusion of these degrees of freedom resolves the conflict between periodic axion potentials and the gradient de Sitter criterion, without the need to invoke the refined de Sitter criterion. We investigate the possibility of including this runaway direction as a model of quintessence that satisfies the swampland criteria. Using a single nonperturbative effect, the maximum along the axion direction provides such a runaway direction, which is unstable in the axion directions, sensitive to initial conditions and too steep to allow for a Hubble time of expansion without violating the field excursion criterion. Adding a second nonperturbative effect generates a saddle point in the potential satisfying the refined de Sitter criterion, which solves the steepness problem and improves the initial conditions problem although some fine-tuning remains required.

scholarly journals Fractal initial conditions and natural parameter values in hybrid inflation

2009 ◽  
Vol 80 (12) ◽  
Author(s):  
Sébastien Clesse ◽  
Christophe Ringeval ◽  
Jonathan Rocher
Keyword(s):  
Initial Conditions ◽  
Natural Parameter ◽  
Hybrid Inflation ◽  
Parameter Values

scholarly journals TwInflation

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Kaustubh Deshpande ◽  
Soubhik Kumar ◽  
Raman Sundrum
Keyword(s):  
General Structure ◽  
Ultra Violet ◽  
Effective Field ◽  
Fine Tuning ◽  
Hierarchy Problem ◽  
Future Directions ◽  
Cosmic Inflation ◽  
Hybrid Mechanism ◽  
The Face ◽  
Hybrid Inflation

Abstract The general structure of Hybrid Inflation remains a very well-motivated mechanism for lower-scale cosmic inflation in the face of improving constraints on the tensor-to-scalar ratio. However, as originally modeled, the “waterfall” field in this mechanism gives rise to a hierarchy problem (η−problem) for the inflaton after demanding standard effective field theory (EFT) control. We modify the hybrid mechanism and incorporate a discrete “twin” symmetry, thereby yielding a viable, natural and EFT-controlled model of non-supersymmetric low-scale inflation, “Twinflation”. Analogously to Twin Higgs models, the discrete exchange-symmetry with a “twin” sector reduces quadratic sensitivity in the inflationary potential to ultra-violet physics, at the root of the hierarchy problem. The observed phase of inflation takes place on a hilltop-like potential but without fine-tuning of the initial inflaton position in field-space. We also show that all parameters of the model can take natural values, below any associated EFT-cutoff mass scales and field values, thus ensuring straightforward theoretical control. We discuss the basic phenomenological considerations and constraints, as well as possible future directions.

Prediction of Reversed-Phase Liquid Chromatography Retention Parameters for Phenylisothiocyanate Derivatives of Amino Acids

2014 ◽  
Vol 52 (1-2) ◽  
pp. 61-70
Author(s):  
S. Vorslova ◽  
J. Golushko ◽  
S. Galushko ◽  
A. Viksna
Keyword(s):  
Amino Acids ◽  
High Performance ◽  
Method Development ◽  
Initial Conditions ◽  
Reversed Phase ◽  
Fine Tuning ◽  
Model Parameters ◽  
Step Method ◽  
Retention Model ◽  
Derivatives Of

Abstract We report our experience with highly polar and charged analyte retention parameter prediction for a reversed-phase high-performance liquid chromatographic method. The solvatic retention model has been used to predict retention of phenylisothiocyanate derivatives of 25 natural amino acids under gradient elution conditions. Retention factors have been calculated from molecular parameters of analyte structures and from the column and eluent characteristics. A step-by-step method which includes the first guess prediction of initial conditions from structural formula and fine tuning of the retention model parameters using data from successive runs can substantially save method development time

scholarly journals Properties of Carbon-Oxygen White Dwarf Merger Remnants

2011 ◽  
Vol 7 (S281) ◽  
pp. 280-283 ◽  
Author(s):  
Chenchong Zhu ◽  
Philip Chang ◽  
Marten van Kerkwijk ◽  
James Wadsley
Keyword(s):  
Parameter Space ◽  
White Dwarf ◽  
Initial Conditions ◽  
Fine Tuning ◽  
Large Set

AbstractRecent studies have shown that for suitable initial conditions both super- and sub-Chandrasekhar mass carbon-oxygen white dwarf mergers produce explosions similar to observed SNe Ia. The question remains, however, how much fine tuning is necessary to produce these conditions. We performed a large set of SPH merger simulations, sweeping the possible parameter space. We find trends for merger remnant properties, and discuss how our results affect the viability of our recently proposed sub-Chandrasekhar merger channel for SNe Ia.

Sign in / Sign up

Export Citation Format

Share Document