On Friday, October 4, 2019 at 4:50:12 AM UTC-6, Lawrence Crowell wrote: > > > > On Friday, October 4, 2019 at 5:34:42 AM UTC-5, Alan Grayson wrote: >> >> >> >> On Friday, October 4, 2019 at 3:31:31 AM UTC-6, Lawrence Crowell wrote: >>> >>> On Thursday, October 3, 2019 at 8:13:22 PM UTC-5, Alan Grayson wrote: >>>> >>>> On Thursday, October 3, 2019 at 7:05:12 PM UTC-6, Lawrence Crowell >>>> wrote: >>>>> >>>>> On Thursday, October 3, 2019 at 8:01:49 PM UTC-5, Lawrence Crowell >>>>> wrote: >>>>>> >>>>>> On Thursday, October 3, 2019 at 6:59:35 PM UTC-5, Bruce wrote: >>>>>>> >>>>>>> On Fri, Oct 4, 2019 at 9:54 AM Alan Grayson <[email protected]> >>>>>>> wrote: >>>>>>> >>>>>>>> >>>>>>>> ISTM, that the argument the universe was NOT in thermo equilibrium >>>>>>>> just before inflation is alleged to have begun, is extremely WEAK. >>>>>>>> Thus, >>>>>>>> it's illogical to claim that inflation "smooths out" the alleged NON >>>>>>>> thermo >>>>>>>> equiiibrium just before inflation begun. AG >>>>>>>> >>>>>>> >>>>>>> That is essentially what I said. Lawrence is just replacing one set >>>>>>> of unknown initial conditions with another, equally unjustified, set. >>>>>>> >>>>>>> Bruce >>>>>>> >>>>>> >>>>> In below & means δ. I forgot to replace them. >>>>> >>>>> LC >>>>> >>>>> >>>>>> >>>>>> The entropy is S = A/4ℓ_p^2 + quantum corrections, where these >>>>>> corrections are ~ (&S/&h^a)k^a. Here h^a is tangent to the horizon and >>>>>> k^a >>>>>> is normal. This condition coincident on a null surface can appear on a >>>>>> quantum extremal surface with null tangent g^s so that (&S/&h^a)k^a ≥ >>>>>> (&S/&g^a)k^a by subadditivity. However, this surface occurs inside the >>>>>> cosmological horizon. This means there is no equilibriium. Equilibrium >>>>>> is >>>>>> only approximated by stretching the horizon out to enormous distance >>>>>> after >>>>>> the spatial surface has inflated. >>>>>> >>>>>> It is the case that inflation does not tell us the whole story prior >>>>>> to inflation. So one can say there are equally unknown initial >>>>>> conditions. >>>>>> However, the details of those are less important as the spatial manifold >>>>>> is >>>>>> stretched out. That means inflation does provide at least a working >>>>>> system. >>>>>> >>>>>> LC >>>>>> >>>>> >>>> Assuming the universe was incredibly tiny prior to inflation, and was >>>> therefore causally connected, isn't it reasonable to assume that it had >>>> reached thermo equilibrium *prior* to the onset of inflation? AG >>>> >>> >>> Thermal equilibrium is not possible with quantum fields in curved >>> spacetiome, nor is is likely in quantum gravity. The reason is not too hard >>> to see. Suppose you have a black hole in a thermal background with the same >>> temperature as its horizon T ~ 1/8M. The black hole has an equiprobability >>> of absorbing or emitting a photon with energy δM The temperature then >>> adjusts as T - δT ~ 1/8(M + δM) or T + δT ~ 1/8(M - δM) and is shifted away >>> from thermal equality. This will then enhance the probability the black >>> hole either then grows by absorbing more photons or by emitting them. There >>> is no thermal equilibrium. Quantum gravitation is likely the same, for the >>> effective specific heat of event horizons is negative. What I wrote above >>> is in effect a more general form of this. >>> >>> Now a gemish of particles or a gas can be in thermal equilibrium in >>> spacetime. >>> >> >> *Doesn't this characterize the universe before inflation began? If not, >> then what? AG* >> > > No, the large plasma of particles was generated in the post inflationary > period with reheating or the collapse of the vacuum or inflaton. > > LC >
If not a plasma of particles before inflation, then what was it -- a soup of photons, or what? Also, although I really don't know much about BH's, your analysis above depends on a boundary between the BH and what's beyond it. In the pre-inflation universe there was no internal boundary within the universe, so I don't see the relevance of the BH analogy. AG > > >> >> >>> That was what was set up with inflation. The whole process of the early >>> expanding universe is about there being episodes of approximate thermal >>> equilibrium of particles, such as during the quark-gluon plasma phase, >>> electroweak period, the QED equilibrium of electrons and photon or the >>> plasma phase that ended by producing the CMB. >>> >>> To think about physics one has to do a sort of Buddhist middle way. It >>> is not good to either be too liberal or given to extreme speculations, but >>> it is also not good to be overly conservative. >>> >>> LC >>> >> -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/4c0948c2-1b5c-4d99-a784-38d012c3c36d%40googlegroups.com.
