Gravity from a Particle Physicists' perspective

Oct, 2009
27 pages
Published in:
  • PoS ISFTG (2009) 011
Contribution to:
e-Print:
Report number:
  • PI-PARTPHYS-156

Citations per year

2009201320172021202402468
Abstract: (arXiv)
In these lectures I review the status of gravity from the point of view of the gauge principle and renormalization, the main tools in the toolbox of theoretical particle physics. In the first lecture I start from the old question "in what sense is gravity a gauge theory?" I will reformulate the theory of gravity in a general kinematical setting which highlights the presence of two Goldstone boson-like fields, and the occurrence of a gravitational Higgs phenomenon. The fact that in General Relativity the connection is a derived quantity appears to be a low energy consequence of this Higgs phenomenon. From here it is simple to see how to embed the group of local frame transformations and a Yang Mills group into a larger unifying group, and how the distinction between these groups, and the corresponding interactions, derives from the VEV of an order parameter. I will describe in some detail the fermionic sector of a realistic "GraviGUT" with SO(3,1)xSO(10) \subset SO(3,11). In the second lecture I will discuss the possibility that the renormalization group flow of gravity has a fixed point with a finite number of attractive directions. This would make the theory well behaved in the ultraviolet, and predictive, in spite of being perturbatively nonrenormalizable. There is by now a significant amount of evidence that this may be the case. There are thus reasons to believe that quantum field theory may eventually prove sufficient to explain the mysteries of gravity.
Note:
  • Lectures given at the Fifth International School on Field Theory and Gravitation, Cuiaba, Brazil April 20-24 2009. To appear in PoS
  • lectures: Cuiaba 2009/04/20
  • general relativity
  • Higgs model
  • Klein-Gordon equation
  • differential forms
  • differential geometry
  • grand unified theory
  • SO(3,1)
  • SO(3,11)
  • SO(10)