On Saturday, October 5, 2019 at 4:57:10 AM UTC-5, Alan Grayson wrote: > > > > On Friday, October 4, 2019 at 4:57:30 PM UTC-6, Lawrence Crowell wrote: >> >> On Friday, October 4, 2019 at 7:32:32 AM UTC-5, Alan Grayson wrote: >>> >>> >>> >>> 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 >>> >> >> I will write it one more time. Particles and radiation emerged in the >> observable universe, or this pocket world, with the collapse of the vacuum >> energy or inflaton by the mass-gap. The drop in vacuum energy produced the >> matter and radiation around us. >> >> LC >> > > OK; no particles or radiation prior to the onseet of inflation. But > supposing your model is correct, given the incredibly small size of the > universe as inflation proceeded, wouldn't those particles and radiation, > once created, have been in thermal equilibrium throughout, supporting my > model that inflation preserves the thermal equilibrium of the very early > universe, but doesn't create it (as measured in the CMBR)? I agree with > Clark (and you?) about flatness and monopoles, but I think he didn't > understand my reason for thinking the very early universe was in thermal > equilbrium, and that this state wasn't created, but *preserved* by > inflation. AG >
They came to equilibrium, and what thermal fluctuations that deviated away from equilibrium were "ironed out" by inflation. The current state of the universe is such that it emerged from a much lower state of entropy than what we would otherwise think. This state of low entropy was available to a causal region that inflated out, and what fluctuations existed were stretched out and reduced in relative magnitude. I fail to see why so many people have trouble with this. It is not a final answer, for that will require not only quantum gravitation, but a theory of quantum gravitation that is worked into a fair measure of maturity. However, inflation does push the barrier of ignorance back a fair degree. 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/baca5cc6-b820-46ff-ad7d-02e62e8cb940%40googlegroups.com.
