Course

19S1 D. Anselmi
Theories of gravitation

Program

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Book

D. Anselmi
From Physics To Life

A journey to the infinitesimally small and back

In English and Italian

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FR: book | ebook (in EN)
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Recent Papers

Quantum gravity

Talk given by Marco Piva at the conference “Avenues of quantum field theory in curved spacetime“, Modena, Sept 9th, 2019

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Talk given at the conference “Cosmological Frontiers in Fundamental Physics 2019” – Perimeter Institute

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Talk given at the Centre de Physique Theorique of the University of Marseille on June 28th, 2019



A new quantization prescription is able to endow quantum field theory with a new type of “particle”, the fakeon (fake particle), which mediates interactions, but cannot be observed. A massive fakeon of spin 2 (together with a scalar field) allows us to build a theory of quantum gravity that is both renormalizable and unitary, and to some extent unique. After presenting the general properties of this theory, I discuss its classical limit, which carries important remnants of the fakeon quantization prescription. I also discuss the possibility that the Higgs boson might be a fakeon.

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Talk given at the conference “Gravity and other fields under the volcano”, Catania, Italy, June 10th, 2019



A new quantization prescription is able to endow quantum field theory with a new type of “particle”, the fakeon (fake particle), which mediates interactions, but cannot be observed. A massive fakeon of spin 2 (together with a scalar field) allows us to build a theory of quantum gravity that is both renormalizable and unitary, and to some extent unique. After presenting the general properties of this theory, I discuss its classical limit, which carries important remnants of the fakeon quantization prescription. I also discuss the possibility that the Higgs boson might be a fakeon.

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We point out the idea that, at small scales, gravity can be described by the standard degrees of freedom of general relativity, plus a scalar particle and a degree of freedom of a new type: the fakeon. This possibility leads to fundamental implications in understanding gravitational force at quantum level as well as phenomenological consequences in the corresponding classical theory.

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Int. J. Mod. Phys. D 28 (2019) 1944007 | DOI: 10.1142/S0218271819440073

arXiv: 1905.06516 [hep-th]

Talk given at the conference Hot topics in modern cosmology. Spontaneous Workshop XIII, 5 – 11 May 2019 — IESC, Cargèse




A new quantization prescription is able to endow quantum field theory with a new type of “particle”, the fakeon (fake particle), which mediates interactions, but cannot be observed. A massive fakeon of spin 2 (together with a scalar field) allows us to build a theory of quantum gravity that is both renormalizable and unitary, and to some extent unique. After presenting the general properties of this theory, I discuss its classical limit, which carries important remnants of the fakeon quantization prescription and reveals unforeseen features.

PDF

Talk given at the conference PAFT 2019 – Current problems in theoretical physics. Aspects of nonperturbative QFT, foundations of quantum theory, quantum spacetime. XXV edition, Vietri sul Mare (Salerno, Italy), April 13-17, 2019




A new quantization prescription is able to endow quantum field theory with a new type of “particle”, the fakeon (fake particle), which mediates interactions, but cannot be observed. A massive fakeon of spin 2 (together with a scalar field) allows us to build a theory of quantum gravity that is both renormalizable and unitary, and to some extent unique. After presenting the general properties of this theory, I discuss its classical limit, which carries important remnants of the fakeon quantization prescription and reveals unforeseen features.

PDF



Presentazione per il pubblico alla conferenza “Tantrismo e Metafisica quantica” per il ciclo “One World University: incontri tra Oriente e Occidente”, a cura di Gloria Germani, presso in Cinema Odeon di Firenze, 21/3/2019

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Talk given at the Conference “Scale invariance in particle physics and cosmology“, CERN, on January 29th, 2019


A new quantization prescription is able to endow quantum field theory with a new type of “particle”, the fakeon (fake particle), which mediates interactions, but cannot be observed. A massive fakeon of spin 2 (together with a scalar field) allows us to build a theory of quantum gravity that is both renormalizable and unitary, and to some extent unique. After presenting the general properties of this theory, I discuss its classical limit, which carries important remnants of the fakeon quantization prescription.

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Watch talk from the CERN Document Server

Under certain assumptions, it is possible to make sense of higher derivative theories by quantizing the unwanted degrees of freedom as fakeons, which are later projected away. Then the true classical limit is obtained by classicizing the quantum theory. Since quantum field theory is formulated perturbatively, the classicization is also perturbative. After deriving a number of properties in a general setting, we consider the theory of quantum gravity that emerges from the fakeon idea and study its classicization, focusing on the FLRW metric. We point out cases where the fakeon projection can be handled exactly, which include radiation, the vacuum energy density and the combination of the two, and cases where it cannot, which include dust. Generically, the classical limit shares many features with the quantum theory it comes from, including the impossibility to write down complete, “exact” field equations, to the extent that asymptotic series and nonperturbative effects come into play.

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J. High Energy Phys. 04 (2019) 61 | DOI: 10.1007/JHEP04(2019)061

arXiv: 1901.09273 [gr-qc]

OSF preprints | DOI: 10.31219/osf.io/au8j4

Hal-02368987

Book

14B1 D. Anselmi
Renormalization

Course on renormalization, taught in Pisa in 2015. (More chapters will be added later.)

Last update: May 9th 2015, 230 pages

Avaibable on Amazon:

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Contents:
Preface
1. Functional integral
2. Renormalization
3. Renormalization group
4. Gauge symmetry
5. Canonical formalism
6. Quantum electrodynamics
7. Non-Abelian gauge field theories
Notation and useful formulas
References


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