On the corpuscular theory of gravity

Giusti, Andrea (2018) On the corpuscular theory of gravity, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Fisica, 31 Ciclo. DOI 10.6092/unibo/amsdottorato/8751.
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Abstract

The aim of this thesis is to provide a general description of the corpuscular theory of gravity. After reviewing some of the major conceptual issues emerging from the semiclassical and field theoretic approaches to Einstein's gravity, we present a synthetic overview of two novel (and extremely intertwined) perspectives on quantum mechanical effects in gravity: the horizon quantum mechanics formalism and the classicalization scheme. After this preliminary discussion, we then proceed with implementing the latter to several different scenarios, namely self-gravitating systems, the early Universe, and galactic dynamics. Concerning the first scenario, we start by describing the generation of the Newtonian potential as the result of a coherent state of toy (scalar) gravitons. After that we employ this result to study some features of the gravitational collapse and to argue that black holes can be thought of a self-sustained quantum states, at the critical point, made of a large number soft virtual gravitons. We then refine this simplified analysis by constructing an effective theory for the gravitational potential of a static spherical symmetric system up to the first post-Newtonian correction. Additionally, we employ the horizon quantum mechanics formalism to study the causal structure emerging from the corpuscular scenario. Finally, we present a short discussion of corpuscular black holes in lower dimensional spaces. After laying down the basics of corpuscular black holes, we present a generalization of the aforementioned arguments to cosmology. Specifically, we first introduce a corpuscular interpretation of the de Sitter spacetime. Then we use it as the starting point for a corpuscular formulation of the inflationary scenario and to provide an alternative viewpoint on the dark components of the LambdaCDM model.

Abstract
Tipologia del documento
Tesi di dottorato
Autore
Giusti, Andrea
Supervisore
Co-supervisore
Dottorato di ricerca
Ciclo
31
Coordinatore
Settore disciplinare
Settore concorsuale
Parole chiave
Classicalization, UV-completion of gravity, Horizon Quantum Mechanics, Black Holes, Inflation, Dark Matter
URN:NBN
DOI
10.6092/unibo/amsdottorato/8751
Data di discussione
30 Novembre 2018
URI

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