Higher derivative scalar interactions can give rise to interesting cosmological scenarios. We present a complete classification of such operators that can yield sizeable effects without introducing ghosts and, at the same time, define an effective field theory robust under the inclusion of quantum corrections. A set of rules to power count consistently the coefficients of the resulting Lagrangian is provided by the presence of an approximate global symmetry. The interactions that we derive in this way contain a subset of the so-called Horndeski and beyond Horndeski theories. Our construction therefore provides a structurally robust context to study their phenomenology. Applications to dark energy/modified gravity and geodesically complete cosmologies are briefly discussed.

Behind Horndeski: structurally robust higher derivative EFTs

Santoni, Luca;Trincherini, Enrico;TROMBETTA, LEONARDO GIULIANO
2018

Abstract

Higher derivative scalar interactions can give rise to interesting cosmological scenarios. We present a complete classification of such operators that can yield sizeable effects without introducing ghosts and, at the same time, define an effective field theory robust under the inclusion of quantum corrections. A set of rules to power count consistently the coefficients of the resulting Lagrangian is provided by the presence of an approximate global symmetry. The interactions that we derive in this way contain a subset of the so-called Horndeski and beyond Horndeski theories. Our construction therefore provides a structurally robust context to study their phenomenology. Applications to dark energy/modified gravity and geodesically complete cosmologies are briefly discussed.
Settore FIS/02 - Fisica Teorica, Modelli e Metodi Matematici
Classical Theories of Gravity; Effective Field Theories; Space-Time Symmetries; High Energy Physics - Theory; High Energy Physics - Theory; astro-ph.CO; High Energy Physics - Phenomenology; Nuclear and High Energy Physics
Fondi MUR
2015P5SBHT
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11384/75604
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