Oui la découverte du boson de Higgs pourrait bien être aussi importante pour l'histoire de la pensée humaine que la loi de la gravitation universelle de Newton

Le blogueur, plus enthousiaste que Carlo Rovelli sur la découverte du boson de Higgs (endosse donc à sa place les propos que ce dernier n'a pas tenus*)

Pour étayer un peu plus scientifiquement le titre de ce billet que d'aucuns jugeraient trop fracassant, voici un extrait d'un article qui discute l'hypothèse hardie selon laquelle la masse de toutes les particules élémentaires connues aurait une origine quantique associée au boson de Higgs (rappelons toutefois que sous le vocable de masse se cachent de nombreux concepts physiques différents qu'il faut savoir "dévisser" pour percer le mur derrière lequel se trouve un peu plus de lumière...):

If we could establish a Coleman-Weinberg origin of the Higgs boson mass, we would then have two scales in nature generated by quantum loop effects: ΛQCD and v_weak. The grand hypothesis that: “all mass in nature comes from quantum mechanics” would gain significant validation. Our view of the UV would then have to accomodate it. This hypothesis may ultimately imply a radically different view of nature than our current “Grand Unified Theories to strings” philosophy. Some of these issues and “predictions” have been discussed elsewhere [7]. For example, we live in a D=4 universe, and it is striking that D=4 is the only possibility for classical scale symmetry given Yang-Mills field theories as an underpinning of nature, since the trace of the Yang-Mills field stress tensor is classically zero only in D=4. Quantum mechanics then supplies the trace anomaly and allows for the generation of mass and large hierarchies through the renormalization group. We see this with QCD and the compelling question is whether it also applies to the weak scale and Higgs boson. Hence, the hypothesis that “all mass in nature comes from quantum mechanics” already seems broadly consistent with our D=4, large universe. The stakes are high: this may ultimately require a classically scale-invariant approach to gravity, such as D=4 Weyl gravity with a quantum, QCD-like origin of M_Planck [37] (see also [7] and references therein).

Is the Higgs Boson Associated with Coleman-Weinberg Dynamical Symmetry Breaking? 

Christopher T. Hill, 27 janv 2014

Et puisque ce blog prétend explorer la physique sous le prisme de la géométrie non commutative, ajoutons-y cet extrait d'un autre travail qui fait écho au précédent article ainsi qu'au programme d'unification géométrique spectrale développé par Alain Connes, Ali Chamseddine, Mathilde Marcolli, Walter van Suijlekom et d'autres intrépides...

In this note we will show the intimate relationships between Weyl anomalies, the dilaton and the Higgs field in the framework of spectral physics. The framework is the expression of a field theory in terms of the spectral properties of a (generalized) Dirac operator. In this respect this work can be seen in the framework of the noncommutative geometry approach to the standard model of Connes and collaborators [1, 2, 3, 4], as well as of Sakharov induced gravity [5] (for a modern review see [6])... It is known, and this is the essence of the noncommutative geometry approach to the standard model, that the theory is described by a fermionic action and a bosonic action, both of which can be expressed in terms of the spectrum of the Dirac operator. In [7] two of us have shown that if one starts from the classic fermionic action and proceeds to quantize the theory with a regularization based on the spectrum, an anomaly appears. it is possible that the full quantum theory is still invariant by correcting the path integral measure. This is tantamount to the addition of a term to the action, which renders the bosonic background interacting to the dilaton field. The main result of that paper is that this term is a modification of the bosonic spectral action [3]. In this case the theory is still invariant. In this paper we have a shift of the point of view. We still consider the theory to be regularized in the presence of a cutoff scale, but we consider this scale to have a physical meaning, that of the breaking of Weyl invariance. We then consider the flow of the theory at a renormalization scale, which is not necessarily the scale which breaks the invariance. The theory has a dilaton, and the Higgs field. The dilaton may involve a collective scalar mode of all fermions accumulated in a Weyl-noninvariant dilaton action. Accordingly the spectral action arises as a part of the fermion effective action divided into the Weyl non-invariant and Weyl invariant parts. We calculate the dilaton effective potential and we discuss how it relates to the transition from the radiation phase with zero vacuum expectation value of Higgs fields and massless particles to the electroweak broken phase via condensation of Higgs fields. The collective field of dilaton can provide the above mentioned phase transition with EW symmetry breaking during the evolution of the universe.

Spectral action, Weyl anomaly and the Higgs-Dilaton potential

A.A. Andrianov, M.A. Kurkov, Fedele Lizzi, 2011 

(*Ce billet est dédicacé à Stéphane B. en particulier et plus généralement à tous mes collègues du ...di qui participèrent de près ou de loin à la rédaction de XXXX ;-)