Cyclic Cosmology, Conformal Symmetry and the Metastability of the Higgs

Itzhak Bars, Paul J. Steinhardt, 3 and Neil Turok Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484 USA California Institute of Technology, Pasadena, CA 91125 Department of Physics and Princeton Center for Theoretical Physics, Princeton University, Princeton, NJ 08544, USA Perimeter Institute for Theoretical Physics, Waterloo, ON N2L 2Y5, Canada Abstract Recent measurements at the LHC suggest that the current Higgs vacuum could be metastable with a modest barrier (height (10 GeV)) separating it from a ground state with negative vacuum density of order the Planck scale. We note that metastability is problematic for big bang to end one cycle, bounce, and begin the next. In this paper, motivated by the approximate scaling symmetry of the standard model of particle physics and the primordial large-scale structure of the universe, we use our recent formulation of the Weyl-invariant version of the standard model coupled to gravity to track the evolution of the Higgs in a regularly bouncing cosmology. We find a band of solutions in which the Higgs field escapes from the metastable phase during each big crunch, passes through the bang into an expanding phase, and returns to the metastable vacuum, cycle after cycle after cycle. We show that, due to the effect of the Higgs, the infinitely cycling universe is geodesically complete, in contrast to inflation.