General Principles of Inflationary Cosmology

Recent advances in string theory and inflationary cosmology have led to a surge of interest in the possible existence of an ensemble of cosmic regions, or "universes", among the members of which key physical parameters, such as the masses of elementary particles and the coupling constants, might assume different values. The observed values in our cosmic region are then attributed to an observer selection effect (the so-called anthropic principle). The assemblage of universes has been dubbed "the multiverse". In this paper we review the multiverse concept and the criticisms that have been advanced against it on both scientific and philosophical grounds.

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Inflationary cosmology from STM theory of gravity

Nuclear Physics B ◽

10.1016/s0550-3213(03)00234-7 ◽

2003 ◽

Vol 660 (1-2) ◽

pp. 389-400 ◽

Cited By ~ 32

Author(s):

Mauricio Bellini

Keyword(s):

Inflationary Cosmology ◽

Theory Of Gravity

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Inflationary cosmology in unimodular F(T) gravity

Modern Physics Letters A ◽

10.1142/s0217732317501140 ◽

2017 ◽

Vol 32 (21) ◽

pp. 1750114 ◽

Cited By ~ 26

Author(s):

Kazuharu Bamba ◽

Sergei D. Odintsov ◽

Emmanuel N. Saridakis

Keyword(s):

Spectral Index ◽

Teleparallel Gravity ◽

Specific Model ◽

Inflationary Cosmology ◽

Model Parameters ◽

De Sitter ◽

Reconstruction Procedure ◽

Additional Advantage ◽

Slow Roll ◽

Good Agreement

We investigate the inflationary realization in the context of unimodular F(T) gravity, which is based on the F(T) modification of teleparallel gravity, in which one imposes the unimodular condition through the use of Lagrange multipliers. We develop the general reconstruction procedure of the F(T) form that can give rise to a given scale-factor evolution, and then we apply it in the inflationary regime. We extract the Hubble slow-roll parameters that allow us to calculate various inflation-related observables, such as the scalar spectral index and its running, the tensor-to-scalar ratio, and the tensor spectral index. Then, we examine the particular cases of de Sitter and power-law inflation, of Starobinsky inflation, as well as inflation in a specific model of unimodular F(T) gravity. As we show, in all cases the predictions of our scenarios are in a very good agreement with Planck observational data. Finally, inflation in unimodular F(T) gravity has the additional advantage that it always allows for a graceful exit for specific regions of the model parameters.

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Recent advances in extended inflationary cosmology

Classical and Quantum Gravity ◽

10.1088/0264-9381/10/s/003 ◽

1993 ◽

Vol 10 (S) ◽

pp. S33-S48 ◽

Cited By ~ 19

Author(s):

P J Steinhardt

Keyword(s):

Inflationary Cosmology ◽

Recent Advances

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Looking beyond inflationary cosmology

Canadian Journal of Physics ◽

10.1139/p06-041 ◽

2006 ◽

Vol 84 (6-7) ◽

pp. 437-446

Author(s):

R H Brandenberger

Keyword(s):

String Theory ◽

Scalar Fields ◽

Inflationary Cosmology ◽

Inflationary Universe ◽

Basic Principles ◽

String Gas Cosmology ◽

98.80 Cq ◽

Conceptual Problems

In spite of the phenomenological successes of the inflationary universe scenario, the current realizations of inflation making use of scalar fields lead to serious conceptual problems that are reviewed in this lecture. String theory may provide an avenue towards addressing these problems. One particular approach to combining string theory and cosmology is String Gas Cosmology. The basic principles of this approach are summarized.PACS No.: 98.80.Cq}

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