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Horndeski theory and beyond: a review
1Department of Physics, Rikkyo University, Toshima, Tokyo 171-8501, Japan.
Summary
This review explores Horndeski theory and its generalizations, offering insights into scalar-tensor gravity for astrophysics and cosmology beyond general relativity. It covers key developments like Galileons, cosmological perturbations, and screening mechanisms.
Area of Science:
- * Physics
- * Astronomy
- * Cosmology
Background:
- * General relativity is the standard model for gravity.
- * Scalar-tensor theories offer extensions to general relativity.
- * Horndeski theory provides a framework for a broad class of scalar-tensor theories.
Purpose of the Study:
- * To review recent advancements in Horndeski theory and its generalizations.
- * To provide a systematic understanding of scalar-tensor gravity.
- * To highlight applications in cosmology and astrophysics beyond standard models.
Main Methods:
- * Comprehensive literature review of Horndeski theory and related scalar-tensor theories.
- * Analysis of cosmological perturbations within these frameworks.
- * Examination of specific phenomena such as the Vainshtein screening mechanism and hairy black holes.
Main Results:
- * Horndeski theory and its generalizations offer a unified approach to scalar-tensor gravity.
- * These theories provide tools to explore cosmology beyond general relativity, including scenarios with null energy condition violations.
- * Recent developments address the status of these theories post-GW170817 and explore screening mechanisms and black hole solutions.
Conclusions:
- * Horndeski theory and its generalizations are crucial for advancing our understanding of gravity.
- * These frameworks enable exploration of novel cosmological and astrophysical phenomena.
- * Continued research is vital for testing and refining these theories against observational data.
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