scholarly journals Horndeski genesis: consistency of classical theory

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Yulia Ageeva ◽  
Pavel Petrov ◽  
Valery Rubakov
Keyword(s):  
Strong Coupling ◽  
Dimensional Analysis ◽  
Classical Theory ◽  
Arbitrary Order ◽  
Specific Model ◽  
Power Counting ◽  
Coupling Energy ◽  
Classical Description ◽  
Higher Order Terms ◽  
The Universe

Abstract Genesis within the Horndeski theory is one of possible scenarios for the start of the Universe. In this model, the absence of instabilities is obtained at the expense of the property that coefficients, serving as effective Planck masses, vanish in the asymptotics t → −∞, which signalizes the danger of strong coupling and inconsistency of the classical treatment. We investigate this problem in a specific model and extend the analysis of cubic action for perturbations (arXiv:2003.01202) to arbitrary order. Our study is based on power counting and dimensional analysis of the higher order terms. We derive the latter, find characteristic strong coupling energy scales and obtain the conditions for the validity of the classical description. Curiously, we find that the strongest condition is the same as that obtained in already examined cubic case.

A family of hyper-Bessel functions and convergent series in them

2014 ◽  
Vol 17 (4) ◽  
Author(s):  
Jordanka Paneva-Konovska
Keyword(s):  
Power Series ◽  
Bessel Function ◽  
Classical Theory ◽  
Bessel Functions ◽  
Differential Operators ◽  
Arbitrary Order ◽  
Convergent Series ◽  
Multi Index ◽  
Fatou Theorem ◽  
Convergence Of Series

AbstractThe Delerue hyper-Bessel functions that appeared as a multi-index generalizations of the Bessel function of the first type, are closely related to the hyper-Bessel differential operators of arbitrary order, introduced by Dimovski. In this work we consider an enumerable family of hyper-Bessel functions and study the convergence of series in such a kind of functions. The obtained results are analogues to the ones in the classical theory of the widely used power series, like Cauchy-Hadamard, Abel and Fatou theorem.

scholarly journals LATE-TIME PHANTOM UNIVERSE IN SO(1, 1) DARK ENERGY MODEL WITH EXPONENTIAL POTENTIAL

2005 ◽  
Vol 20 (15) ◽  
pp. 1147-1154 ◽  
Author(s):  
YI-HUAN WEI
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
Energy Model ◽  
Late Time ◽  
De Sitter ◽  
Exponential Potential ◽  
Coupling Energy ◽  
Expansion Phase ◽  
Perturbation Field ◽  
The Universe

We discuss the late-time property of universe and phantom field in the SO(1, 1) dark energy model for the potential V = V0e-βΦα with α and β two positive constants. We assume in advance some conditions satisfied by the late-time field to simplify equations, which are confirmed to be correct from the eventual results. For α < 2, the field falls exponentially off and the phantom equation of state rapidly approaches -1. When α = 2, the kinetic energy ρk and the coupling energy ρc become comparable but there is always ρk < -ρc so that the phantom property of field proceeds to hold. The analysis on the perturbation to the late-time field Φ illustrates the square effective mass of the perturbation field is always positive and thus the phantom is stable. The universe considered currently may evade the future sudden singularity and will evolve to de Sitter expansion phase.

scholarly journals CURVATURE QUINTESSENCE MATCHED WITH OBSERVATIONAL DATA

2003 ◽  
Vol 12 (10) ◽  
pp. 1969-1982 ◽  
Author(s):  
S. CAPOZZIELLO ◽  
V. F. CARDONE ◽  
S. CARLONI ◽  
A. TROISI
Keyword(s):  
High Redshift ◽  
Cosmological Parameters ◽  
Higher Order ◽  
Curved Space ◽  
Curvature Invariants ◽  
Loop Expansion ◽  
Higher Order Terms ◽  
Cosmological Data ◽  
Age Of The Universe ◽  
The Universe

Quintessence issues can be achieved by taking into account higher order curvature invariants into the effective action of gravitational field. Such an approach is naturally related to fundamental theories of quantum gravity which predict higher order terms in loop expansion of quantum fields in curved space-times. In this framework, we obtain a class of cosmological solutions which are fitted against cosmological data. We reproduce encouraging results able to fit high redshift supernovae and WMAP observations. The age of the universe and other cosmological parameters are discussed in this context.

Introduction to Effective Field Theories and Inflation

2020 ◽  
pp. 220-306
Author(s):  
C. P. Burgess
Keyword(s):  
Effective Field Theories ◽  
Big Bang ◽  
Effective Field ◽  
Power Counting ◽  
Field Theories ◽  
Effective Theory ◽  
Inflationary Cosmology ◽  
Big Bang Theory ◽  
The Universe ◽  
Inflationary Models

The lecture notes presented in this chapter provide an introduction to inflationary cosmology with an emphasis on some of the ways effective field theories (EFTs) are used in its analysis. Topics covered in the chapter include introduction to cosmological backgrounds and fluctuations, including a brief discussion of inflationary models; general relativity as an effective theory; new issues raised by cosmology for EFTs, such as time-dependent backgrounds; and power-counting in cosmological EFTs. It also discusses issues surrounding the existence in the universe of both dark matter and dark energy, and the broader controversial question of their existence. It touches on the Hot Big Bang theory of cosmology, and the various types of particles believed to be 'elementary' at the temperatures of interest.

scholarly journals Dispersion relations for gravitational waves in different models of dark energy

2017 ◽  
Vol 26 (14) ◽  
pp. 1750157
Author(s):  
Vladimir Dzhunushaliev ◽  
Vladimir Folomeev ◽  
Burkhard Kleihaus ◽  
Jutta Kunz
Keyword(s):  
Dark Energy ◽  
Power Series ◽  
Gravitational Waves ◽  
Observational Data ◽  
Specific Model ◽  
Dispersion Relations ◽  
Accelerated Expansion ◽  
Energy Models ◽  
Expansion Of The Universe ◽  
The Universe

The propagation of weak gravitational waves on the background of dark energy is studied. The consideration is carried out within the framework of an approximate approach where the cosmological scale factor is expanded as a power series for relatively small values of the redshift corresponding to the epoch of the present accelerated expansion of the universe. For several different dark energy models, we obtain dispersion relations for gravitational waves which can be used to estimate the viability of every specific model by comparing with observational data.

Higher-order terms in the strong-coupling expansion for the renormalized effective potential

1981 ◽  
Vol 24 (10) ◽  
pp. 2683-2692 ◽  
Author(s):  
Carl M. Bender ◽  
Fred Cooper ◽  
G. S. Guralnik ◽  
Ralph Roskies ◽  
David H. Sharp
Keyword(s):  
Strong Coupling ◽  
Effective Potential ◽  
Strong Coupling Expansion ◽  
Higher Order ◽  
Higher Order Terms

IS MASS QUANTIZED?

2004 ◽  
Vol 19 (26) ◽  
pp. 1995-2000 ◽  
Author(s):  
PAUL S. WESSON
Keyword(s):  
Cosmological Constant ◽  
Dimensional Analysis ◽  
Dimensional Reduction ◽  
Speed Of Light ◽  
Membrane Theory ◽  
Planck’S Constant ◽  
Higher Dimensional ◽  
Specific Analysis ◽  
Induced Matter ◽  
The Universe

The cosmological constant combined with Planck's constant and the speed of light implies a quantum of mass of approximately 2×10-65 g . This follows either from a generic dimensional analysis, or from a specific analysis where the cosmological constant appears in 4D spacetime as the result of a dimensional reduction from higher-dimensional relativity (such as 5D induced-matter and membrane theory). In the latter type of theory, all the particles in the universe can be in higher-dimensional contact.

scholarly journals Reionization effect enhancement due to primordial black holes

2017 ◽  
Vol 26 (09) ◽  
pp. 1750102 ◽  
Author(s):  
K. M. Belotsky ◽  
A. A. Kirillov ◽  
N. O. Nazarova ◽  
S. G. Rubin
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Mass Distribution ◽  
Mass Spectra ◽  
Mass Range ◽  
Specific Model ◽  
Primordial Black Holes ◽  
Wide Range ◽  
G Value ◽  
The Universe

Primordial black holes (PBHs) could account for variety of phenomena like dark matter, reionization of the universe, early quasars, coalescence of black holes registered through gravitational waves recently. Each phenomenon relates to PBH of a specific mass range. PBH mass spectra varies in a wide range depending on specific model. Earlier, we have shown that PBH with monochromatic mass distribution around [Formula: see text] g value allow to re-ionize the universe moderately. Here, we show that reionization effect and contribution to dark matter can be simultaneously enhanced with more natural extended mass distribution in the range around the same mass value.

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