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 > > >> 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/9c9a5634-4d84-462d-8606-9329615f88e5%40googlegroups.com.
