Avertissement (au lecteur et encouragement) à l'étudiant
"You are embarking on a highly speculative venture and your one year fellowship may be over with nothing to show!"
Abdus Salam s'adressant à son étudiant Yuri Ne'eman, c.1960
Heureusement pour le jeune physicien à qui s'adressait cet avertissement, son programme de recherche s'avéra rapidement fructueux:
Taking an as yet untried algebraic route, [Ne'eman] mastered the theory of Lie algebras and studied Cartan's 1894 classification of the simplest ones, noting that what he was after was an algebra of rank r = 2 to accommodate Isospin and Strangeness. By October 1960 he had identified SU(3) as the classifying symmetry of the hadrons ...
Remo Ruffini, Matter Particled, 1997
The first tentative steps towards the idea of a deeper layer of particles within the hadrons was made in 1962 by Ne'eman ... and his colleague Haim Goldbeg-Ophir. They wrote a paper suggesting that baryons might each be made up to three more fundamental particles... The paper attracted little attention, partly..., as Ne'eman has aknowledged, 'because it did not go far enough'. The authors had not yet decided whether to regard the fundamental components as proper particles or as abstract fields that did not materialize as particles.
John et Mary Gribbin, Richard Feynman, a Life in Science, 1998
Noncommutative geometry was shown to provide a promising framework for uniﬁcation of all fundamental interactions including gravity , , , , . Historically, the search to identify the structure of the noncommutative space followed the bottom-up approach where the known spectrum of the fermionic particles was used to determine the geometric data that deﬁnes the space. This bottom-up approach involved an interesting interplay with experiments. While at ﬁrst the experimental evidence of neutrino oscillations contradicted the ﬁrst attempt , it was realized several years later in 2006 () that the obstruction to get neutrino oscillations was naturally eliminated by dropping the equality between the metric dimension of space-time (which is equal to 4 as far as we know) and its KO-dimension which is only deﬁned modulo 8. When the latter is set equal to 2 modulo 8 ,  (using the freedom to adjust the geometry of the ﬁnite space encoding the ﬁne structure of space-time) everything works ﬁne, the neutrino oscillations are there as well as the see-saw mechanism which appears for free as an unexpected bonus. Incidentally, this also solved the fermionic doubling problem by allowing a simultaneous Weyl-Majorana condition on the fermions to halve the degrees of freedom. The second interplay with experiments occurred a bit later when it became clear that the mass of the Brout-Englert-Higgs boson would not comply with the restriction (that mH=170GeV) imposed by the validity of the Standard Model up to the uniﬁcation scale. This obstruction to lower mH was overcome in  simply by taking into account a scalar ﬁeld which was already present in the full model which we had computed previously in . One lesson which we learned on that occasion is that we have to take all the ﬁelds of the noncommutative spectral model seriously, without making assumptions not backed up by valid analysis, especially because of the almost uniqueness of the Standard Model (SM) in the noncommutative setting.
Ali H. Chamseddine, Alain Connes et Walter D. van Suijlekom, Beyond the Spectral Standard Model: Emergence of Pati-Salam Uniﬁcation, 30 octobre 2013
Last musings (about why studying non commutative spectral models) / Dernières réflexions (autour de l'intérêt d'étudier des modèles spectraux non commutatifs)
... it would be fitting for scientists to think of themselves as members of an expedition sent to explore an unfamiliar but navigable ocean whose size and shapes are dimly understood. However profitable it may be to make cabotage along the rich coastal cities of the Supersymmetric Commonwealth or exciting to participate in M-theory regatta, it would be tragic to neglect support to the spectral noncommutative parties already working their way across the strait of the TeV (scale), following the Higgs (co)m(p)ass towards the Cape of Grand Unification, dreaming to see a little further the Pillars of Planck otherwise reaching the Ocean of all Geometries at least back to the sources of Space-Time.
... Les scientifiques pourraient se voir comme les membres d'une expédition envoyée pour explorer une mer inconnue mais navigable dont la taille et la forme ne seraient que vaguement comprises. Aussi rentable soit le cabotage le long des riches villes côtières de la République Supersymétrique ou aussi excitant soit la participation à des régates M-théoriques, il serait dommageable de négliger pour autant le soutien aux explorateurs spectraux non commutatifs déjà engagés dans la traversée du détroit (de l'échelle) du Te(ra-électron)V(olt) en suivant la direction du compas de Higgs et qui font route vers le cap de Grande Unification rêvant de voir un peu plus loin les colonnes de Planck pour sinon atteindre l'Océan de toutes les Géométries du moins remonter jusqu'aux sources de l'Espace-Temps.
à la manière de Steven Weinberg dans Why build accelerators? (p73)
//Dernières retouches éditoriales