Hi Doug, I know this isn't the main point of the thread, and perhaps already stuff you know, in which case apologies for redundancy:
> Even the events after that instant of the big bang, where it is postulated > that our universe expanded from sub-atomic dimensions, through inflation > (inflation? WTF caused that?) I think current understanding of inflation and the cosmological constant have all grown out of the way we think about the Higgs mechanism and the energy in the vacuum. I did have a chance to ask a real cosmologist this to be sure I wasn't mistaken, and I believe what I will say below is right. The point of Higgs was that the vacuum underwent a freezing transition as it cooled, in one of the "bowl-to-mexican-hat" potentials that one always sees illustrated in explanations of magnetization etc. (keyword for a google search would be Spontaneous Symmetry Breaking, and apologies that I can't write more here, since I should be working). The general kind of freezing mechanism is used for a lot of stuff and reasonably well understood (understanding why pi mesons are "roughly" massless, how magnetization forms, etc.) The interesting thing is that the massless particle that should have been formed when the Higgs vacuum froze was "eaten" (as they say in the jargon) by the previously-massless weak bosons because it had weak charge, and that made them massive. (Keyword here would be interaction of gauge fields with Goldstone bosons.) But all that is essentially background. The point for this discussion is that when the vacuum could be frozen into the low-energy "rim" of the hat, but starts out on the high-energy center (the part where the crown of your head goes), it has energy to give. If it can succeed in freezing, that creates a shower of massive matter. But if it is delayed in collapsing to the frozen vacuum, like water that is supercooled before it can freeze into its proper crystal, that excess vacuum energy becomes a source of stress energy-momentum for gravitation. That stress energy momentum is the cosmological constant, and it drives exponential expansion. Since the Higgs is a very high-energy-scale field (on people-scales), the cosmological constant associated with not-yet-having-relaxed is huge. I don't know whether inflation people still think it was the Higgs of the weak boson that drove initial inflation, but I believe that was the proposal back when Alan Guth was working on these things. In that parlance, the current small-but-not-zero cosmological constant is a tiny residual vacuum energy-momentum that hasn't succeeded in relaxing away into a more stable, truly zero-energy, vacuum. This is probably not a great answer to the question of what caused inflation, but to the extent that having melted the vacuum to see the un-frozen Higgs as a particle seems to get everything right that we can measure, from only this minimal model, it is hard to see from here what would guide us to a more thorough characterization. It is remarkable, though, that the vacuum can have un-relaxed energy. I should understand these things better than I do, but I was a bad student when I should have been learning them. Eric ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com
