scholarly journals Holographic cosmology solutions of problems with pre-inflationary cosmology

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Horatiu Nastase
Keyword(s):  
Field Theory ◽  
Dilution Effect ◽  
Baryon Asymmetry ◽  
Inflationary Cosmology ◽  
Detailed Calculation ◽  
Horizon Problems ◽  
Perturbation Problems ◽  
Flatness Problem

Abstract In this paper we describe in detail how to solve the problems of pre-inflationary cosmology within the holographic cosmology model of McFadden and Skenderis [1]. The solutions of the smoothness and horizon problems, the flatness problem, the entropy and perturbation problems and the baryon asymmetry problem are shown, and the mechanisms for them complement the inflationary solutions. Most of the paper is devoted to the solution of the monopole relic problem, through a detailed calculation of 2-loop correlators of currents in a toy model which we perform in d dimensions, in order to extract its leading dependence on $$ {g}_{\mathrm{eff}}^2={g}_{\mathrm{YM}}^2N/q $$ g eff 2 = g YM 2 N / q and find a dilution effect. Taken together with the fact that holographic cosmology gives as good a fit to CMBR as the standard paradigm of Λ CDM with inflation, it means holographic cosmology extends the inflationary paradigm into new corners, explorable only through a dual perturbative field theory in 3 dimensions.

Unexpected Applications of Hill's Differential Equations in Quantum Field Theory and Cosmology

2003 ◽  
Vol 18 (12) ◽  
pp. 2159-2166
Author(s):  
V. M. Mostepanenko
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
External Field ◽  
Differential Equations ◽  
Parametric Resonance ◽  
Physical Theory ◽  
Pair Creation ◽  
Physical Effect ◽  
Inflationary Cosmology ◽  
Quantum Field

The effect of the exponential pair creation from vacuum by the external field periodic in time is discussed. Two prospective applications of this physical effect in quantum field theory and in inflationary cosmology are considered. Being a nontrivial example of a parametric resonance, the effect of exponential pair creation may serve as an illustration of the effectiveness of mathematics in physical theory.

scholarly journals Role of trans-Planckian modes in cosmology

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Arjun Berera ◽  
Suddhasattwa Brahma ◽  
Jaime R. Calderón
Keyword(s):  
Field Theory ◽  
Power Spectrum ◽  
Effective Field Theory ◽  
Effective Field ◽  
Inflationary Cosmology ◽  
De Sitter ◽  
Warm Inflation ◽  
Primordial Power Spectrum ◽  
Hubble Horizon

Abstract Motivated by the old trans-Planckian (TP) problem of inflationary cosmology, it has been conjectured that any consistent effective field theory should keep TP modes ‘hidden’ behind the Hubble horizon, so as to prevent them from turning classical and thereby affecting macroscopic observations. In this paper we present two arguments against the Hubble horizon being a scale of singular significance as has been put forward in the TP Censorship Conjecture (TCC). First, refinements of TCC are presented that allow for the TP modes to grow beyond the horizon while still keeping the de-Sitter conjecture valid. Second, we show that TP modes can turn classical even well within the Hubble horizon, which, as such, negates this rationale behind keeping them from crossing it. The role of TP modes is known to be less of a problem in warm inflation, because fluctuations start out usually as classical. This allows warm inflation to be more resilient to the TP problem compared to cold inflation. To understand how robust this is, we identity limits where quantum modes can affect the primordial power spectrum in one specific case.

scholarly journals A symmetric DBI action theory and its applications to inflationary cosmology

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
Xiaokun Yang ◽  
Wu-Long Xu ◽  
Yong-Chang Huang
Keyword(s):  
Field Theory ◽  
String Theory ◽  
Power Spectrum ◽  
Action Theory ◽  
Density Perturbation ◽  
Inflationary Cosmology ◽  
Scalar Perturbation ◽  
Causal Mechanism ◽  
Perturbation Spectrum ◽  
The Universe

AbstractThe Dirac-Born-Infeld (DBI) field theory in string theory is important and can provide the field of the universe’s inflation. At the same time, it provides a causal mechanism for generating the original density perturbation, thereby providing the necessary density perturbation for existing the dense and sparse matter distributions of the universe. We deduce a symmetric DBI action, introduce it into inflationary cosmology to calculate various inflation parameters, further calculate the scalar perturbation spectrum and the tensor-scalar ratio, which are compared with Planck + WMAP9 + BAO data, the power spectrum predicted by the new general DBI inflation theory satisfies the CMB Experiment constraints, i.e., is consistent with the current theories and experimental observations. Consequently, the theory of this paper conforms to current experiments and is supplying the current theories, and also a new way of explaining the inflation of the universe.

Inflation and primordial perturbations

2018 ◽  
Author(s):  
Michele Maggiore
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Large Field ◽  
Inflationary Cosmology ◽  
Small Field ◽  
Quantum Field ◽  
Curved Space ◽  
Slow Roll ◽  
Starobinsky Model ◽  
Single Field

Review of inflationary cosmology. Single-field slow-roll inflation. Large-field inflation and small-field inflation. Starobinsky model. Quantum field theory in curved space. Generation of primordial perturbations during inflation. Mukhanov-Sasaki equation. Scalar and tensor perturbations.

BRST-FORMULATION OF A MASSLESS SPIN-1 PARTICLE

1989 ◽  
Vol 04 (15) ◽  
pp. 3833-3850
Author(s):  
THOMAS DOMEIJ
Keyword(s):  
Field Theory ◽  
String Field Theory ◽  
Brst Quantization ◽  
Detailed Calculation ◽  
Massless Spin

We present a detailed calculation of BRST quantization of a free massless spin-1 particle. Then we go on to describe a field theory, inspired by Witten's string field theory, in an attempt to also include interactions.

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