Inflation

[Alan Grayson]

Bruce considers that inflation remains somewhat speculative; that it's a solution looking for a problem to solve. So my questions are as follows: 1), does inflation solve the homogeneity problem; namely, that the observable universe seems to have come to thermo equlibrium, manifested by homogeneity, even though it is causally UN-connected; and 2), does it explain the absence of magnetic monopoles? TIA, AG

[Alan Grayson]

On Sunday, September 29, 2019 at 8:53:35 AM UTC-6, Alan Grayson wrote:

Bruce considers that inflation remains somewhat speculative; that it's a solution looking for a problem to solve. So my questions are as follows: 1), does inflation solve the homogeneity problem; namely, that the observable universe seems to have come to thermo equlibrium, manifested by homogeneity, even though it is causally UN-connected; and 2), does it explain the absence of magnetic monopoles? TIA, AG

Bruce; it seems like a simple issue you can resolve. That is, if you're skeptical that inflation solves any problems, does that include its allege explanation for large scale homogeneity and the absence of magnetic monopoles? TIA, AG

[Bruce Kellett]

Alan, stop treating me as though I existed merely to answer your questions. The answers to these questions are readily available in the literature. It is clear from your postings here that you are not widely read in the modern literature on these subjects. I am not your teacher. I think Sabine Hossenfelder has a blog post on this:

http://backreaction.blogspot.com/search?q=+inflation

Bruce 

[Alan Grayson]

In fact, if facts matter, I studied the issue of homogeneity quite seriously and finally convinced myself that inflation seems to solve the issue of thermo equilibrium for a visable universe that is not causally connected. Then you come along, make a glib statement that in effect denies that conclusion (which I gather is widely supported among physicists). So it seems we deserve to hear some of your reasoning Ithis matter. On numerous other subjects, you are not at all reticent about fully airing your logic, but curiously, not so here.  AG

[Alan Grayson]

In fact, if facts matter, I studied the issue of homogeneity quite seriously and finally convinced myself that inflation seems to solve the issue of thermo equilibrium for a visable universe that is not causally connected. Then you come along, make a glib statement that in effect denies that conclusion (which I gather is widely supported among physicists). So it seems we deserve to hear some of your reasoning In this matter. On numerous other subjects, you are not at all reticent about fully airing your logic, but curiously, not so here.  AG

One thing I should add; I don't regard you as my teacher. However, you seem to have a much clearer view than most physicists, on most of the topics of interest. Consequently, I seek to experience the clarity you offer, though, to be candid, I have seen a miserly aspect of your character in this regard. AG 

[Alan Grayson]

It probably went over your head, but in effect, and indirectly, I was trying to teach YOU something; namely, that inflation is an excellent explanation for the large scale homogeneity of the observable universe. I chose to put it as a question, to see the logic of your defense of your general position on inflation. AG 

[Lawrence Crowell]

Alan also asks same questions over and over, where Alan then shaves these down to absurd points in refinements. These things are in internet resources that are fairly accessible to laymen. 

LC

[Alan Grayson]

Absurd points of refinements? Haven't you heard; the demons are in the details? Instead of sycophantic BS'ing, don't you think inflation is a good, and so far only explanation for the homogeneity of our causally UNconnected observable universe. I read the comments by Hossenfelder on homogeneity and didn't find them persuasive.  AG

[Alan Grayson]

On Wednesday, October 2, 2019 at 4:52:50 AM UTC-6, Lawrence Crowell wrote:

Lawrence; I'm wondering. Seriously; are now firmly enscounced in your Alzheimer's phase? This is the first, or at most second time I've raised the issue of whether inflation solves the homegeneity issue of our visible universe. And instead of addressing the issue, which Bruce glibly dismisses, you absurdly accuse of me of "absurd points of refinements". Seriously, what bullshit! Is that how you characterize the progressively detailed measurements of, say, the CMBR. Are more and more detailed physical observations of whatever, also "absure points of refinements"? On the homogeneity issue, I HAVE thought about this a lot, and I have used the internet in an effort to get some resolution, and reach some conclusions. What your comment shows is that bringing it up here is nothing more than fertile ground for insults from wannabe thinkers. AG

[Lawrence Crowell]

You belabor questions in a way that illustrates your need for something similar to a proof. Science does not prove its conclusions. Oh sure, there are logical derivations or proofs in formulation of theories, but what is tentatively true relies on consistency with observations. Inflation is to homogeneity what stretching dough is to making a stroudel or pizza crust. Stretch it out and it is pretty uniform. The mathematics in the theory makies this work in a way one can make calculations.

You have asked this same question repeatedly, as with some other questions, the answers are generally the same and you make the same complaints.

LC

[Alan Grayson]

I am sophisticated enough to know that not everything in physics is mathematically provable. Inferences are made to account for observations. I don't expect a mathematical proof that inflation explains homogeneity. But my study of the subject indicates it's a very plausible explanation. Bruce seems to deny this, apparently agreeing with Hossenfelder that inflation is mostly an attempt to solve non existent problems. So all I asked of Bruce was for his reasoning in this matter. Instead I get insults, followed by your false evaluations of my history, in apparent support of Bruce's insults. In FACT, although I posited the issue in terms of questions, I was taking the role of a teacher in this matter. Think of Socrates who was executed for asking too many questions. That's my style! AG

You have asked this same question repeatedly, as with some other questions, the answers are generally the same and you make the same complaints.

I have NOT!  You're greatly exaggerating. In general, most of my physics conclusions have been sound, and where I pose questions, they usually lead to worthwhile discussions. In this case I was just responding to Bruce's certainty that inflation is mostly a red herring. I highly respect his opinions, but in this case, based on my study of this particular issue, I disagree. I am open to being proved wrong, but insults don't cut it. At least you agree that inflation does explain homogeneity. Aren't you curious about Bruce's take on this particular issue? AG

LC

[Bruce Kellett]

On Thu, Oct 3, 2019 at 3:03 AM Alan Grayson <agrays...@gmail.com> wrote:

In this case I was just responding to Bruce's certainty that inflation is mostly a red herring. I highly respect his opinions, but in this case, based on my study of this particular issue, I disagree. I am open to being proved wrong, but insults don't cut it. At least you agree that inflation does explain homogeneity. Aren't you curious about Bruce's take on this particular issue? AG

Inflation can result in an increase in flatness and homogeneity. But that is relevant only if flatness and homogeneity were problems in need of explanation.

Bruce 

[Lawrence Crowell]

The real problem is how did disparate regions of the universe become uniform when there would have been no causal connection between them. In particular with homogeneity inflation provides a mechanism whereby deviations from homogeneity and isotropy are uniform.

LC  

[Bruce Kellett]

Fine. Provided they were not uniform at the start. It is all a matter of distributions and in initial conditions. And you know nothing about either, so why solve a problem before you know it exists? Besides, can you achieve thermal equilibrium in a non-equilibrium state in 10^{-35} sec?

Bruce 

[Lawrence Crowell]

Inflation started on a fiducial at 10^{-36}sec and lasted until 10^{-32} sec. Since the particle fields were near the Planck scale in energy this inflationary cycle lasted some 10^{10} times the periodicities of fields. That is enough to approximately have thermal equilibrium. 

Winding  the timeline of the universe back in time based on no inflation results in a problem because of high z physics, in particular the CMB. Without this high vacuum energy and extreme acceleration there is no way to get everything in the same region so they causally evolved according to the same set of initial conditions. In fact before inflation this was a problem that buggered cosmologies back in the 1960s and 70s.

LC

[Bruce Kellett]

On Thu, Oct 3, 2019 at 10:14 AM Lawrence Crowell <goldenfield...@gmail.com> wrote:

On Wednesday, October 2, 2019 at 6:41:32 PM UTC-5, Bruce wrote:

On Thu, Oct 3, 2019 at 9:21 AM Lawrence Crowell <goldenfield...@gmail.com> wrote:

On Wednesday, October 2, 2019 at 5:46:50 PM UTC-5, Bruce wrote:

On Thu, Oct 3, 2019 at 3:03 AM Alan Grayson <agrays...@gmail.com> wrote:

In this case I was just responding to Bruce's certainty that inflation is mostly a red herring. I highly respect his opinions, but in this case, based on my study of this particular issue, I disagree. I am open to being proved wrong, but insults don't cut it. At least you agree that inflation does explain homogeneity. Aren't you curious about Bruce's take on this particular issue? AG

Inflation can result in an increase in flatness and homogeneity. But that is relevant only if flatness and homogeneity were problems in need of explanation.

Bruce 

The real problem is how did disparate regions of the universe become uniform when there would have been no causal connection between them. In particular with homogeneity inflation provides a mechanism whereby deviations from homogeneity and isotropy are uniform.

Fine. Provided they were not uniform at the start. It is all a matter of distributions and in initial conditions. And you know nothing about either, so why solve a problem before you know it exists? Besides, can you achieve thermal equilibrium in a non-equilibrium state in 10^{-35} sec?

Bruce 

Inflation started on a fiducial at 10^{-36}sec and lasted until 10^{-32} sec. Since the particle fields were near the Planck scale in energy this inflationary cycle lasted some 10^{10} times the periodicities of fields. That is enough to approximately have thermal equilibrium.

The problem is not the periodicity of the fields. The problem is the uniformity of the initial conditions. As Sabine points out, inflation just replaces one set of unknown initial conditions with another.

I would also take issue with her suggestion that inflation solves some problems with the origin of the fluctuations seen in the CMB. Inflation might provide a framework, but it does not provide an explanation for these fluctuations. The fluctuations are built in by hand, and the gaussian nature of the fluctuations is also built in by hand. So these features of the CMB are not "explained" by inflation in any sense at all. There gaussian nature, and the relative magnitude of 10^{-5} are both free parameters that are set by hand.

Winding  the timeline of the universe back in time based on no inflation results in a problem because of high z physics, in particular the CMB. Without this high vacuum energy and extreme acceleration there is no way to get everything in the same region so they causally evolved according to the same set of initial conditions. In fact before inflation this was a problem that buggered cosmologies back in the 1960s and 70s.

Perhaps it took a while to realise the importance of initial conditions......

Bruce 

 

[Lawrence Crowell]

On Wednesday, October 2, 2019 at 7:31:56 PM UTC-5, Bruce wrote:

On Thu, Oct 3, 2019 at 10:14 AM Lawrence Crowell <goldenfield...@gmail.com> wrote:

On Wednesday, October 2, 2019 at 6:41:32 PM UTC-5, Bruce wrote:

On Thu, Oct 3, 2019 at 9:21 AM Lawrence Crowell <goldenfield...@gmail.com> wrote:

On Wednesday, October 2, 2019 at 5:46:50 PM UTC-5, Bruce wrote:

On Thu, Oct 3, 2019 at 3:03 AM Alan Grayson <agrays...@gmail.com> wrote:

In this case I was just responding to Bruce's certainty that inflation is mostly a red herring. I highly respect his opinions, but in this case, based on my study of this particular issue, I disagree. I am open to being proved wrong, but insults don't cut it. At least you agree that inflation does explain homogeneity. Aren't you curious about Bruce's take on this particular issue? AG

Inflation can result in an increase in flatness and homogeneity. But that is relevant only if flatness and homogeneity were problems in need of explanation.

Bruce 

The real problem is how did disparate regions of the universe become uniform when there would have been no causal connection between them. In particular with homogeneity inflation provides a mechanism whereby deviations from homogeneity and isotropy are uniform.

Fine. Provided they were not uniform at the start. It is all a matter of distributions and in initial conditions. And you know nothing about either, so why solve a problem before you know it exists? Besides, can you achieve thermal equilibrium in a non-equilibrium state in 10^{-35} sec?

Bruce 

Inflation started on a fiducial at 10^{-36}sec and lasted until 10^{-32} sec. Since the particle fields were near the Planck scale in energy this inflationary cycle lasted some 10^{10} times the periodicities of fields. That is enough to approximately have thermal equilibrium.

The problem is not the periodicity of the fields. The problem is the uniformity of the initial conditions. As Sabine points out, inflation just replaces one set of unknown initial conditions with another.

I would also take issue with her suggestion that inflation solves some problems with the origin of the fluctuations seen in the CMB. Inflation might provide a framework, but it does not provide an explanation for these fluctuations. The fluctuations are built in by hand, and the gaussian nature of the fluctuations is also built in by hand. So these features of the CMB are not "explained" by inflation in any sense at all. There gaussian nature, and the relative magnitude of 10^{-5} are both free parameters that are set by hand.

The initial conditions, what ever they were, were flattened out though by inflation. The anisotropy in the CMB is due to details in the field configuration of the scalar field. The theory just provides the action S = ∫d^4x√g(φR + L(φ)), but not the explicit initial conditions or the configuration of the field at reheating. The point though is these details were exponentially attenuated by inflation so their magnitude is small. Estimates of this works out pretty well.

LC

[Alan Grayson]

In the case of flatness, if the expansion rate were constant, as defined by the Hubble constant of about 70 km/sec/mps, and assuming a hyperspherical geometry expanding for 13.8 by, the measured flatness is probably implausibly too close to zero; IOW too flat. Inflation might be the explanation.  AG 

[Alan Grayson]

On Wednesday, October 2, 2019 at 10:41:02 AM UTC-6, Lawrence Crowell wrote:

On Wednesday, October 2, 2019 at 8:26:27 AM UTC-5, Alan Grayson wrote:

On Wednesday, October 2, 2019 at 4:52:50 AM UTC-6, Lawrence Crowell wrote:

On Tuesday, October 1, 2019 at 5:59:42 PM UTC-5, Bruce wrote:

On Wed, Oct 2, 2019 at 8:40 AM Alan Grayson <agrays...@gmail.com> wrote:

On Sunday, September 29, 2019 at 8:53:35 AM UTC-6, Alan Grayson wrote:

Bruce considers that inflation remains somewhat speculative; that it's a solution looking for a problem to solve. So my questions are as follows: 1), does inflation solve the homogeneity problem; namely, that the observable universe seems to have come to thermo equlibrium, manifested by homogeneity, even though it is causally UN-connected; and 2), does it explain the absence of magnetic monopoles? TIA, AG

Bruce; it seems like a simple issue you can resolve. That is, if you're skeptical that inflation solves any problems, does that include its allege explanation for large scale homogeneity and the absence of magnetic monopoles? TIA, AG

Alan, stop treating me as though I existed merely to answer your questions. The answers to these questions are readily available in the literature. It is clear from your postings here that you are not widely read in the modern literature on these subjects. I am not your teacher. I think Sabine Hossenfelder has a blog post on this:

http://backreaction.blogspot.com/search?q=+inflation

Bruce 

Alan also asks same questions over and over, where Alan then shaves these down to absurd points in refinements. These things are in internet resources that are fairly accessible to laymen. 

LC

Absurd points of refinements? Haven't you heard; the demons are in the details? Instead of sycophantic BS'ing, don't you think inflation is a good, and so far only explanation for the homogeneity of our causally UNconnected observable universe. I read the comments by Hossenfelder on homogeneity and didn't find them persuasive.  AG

You belabor questions in a way that illustrates your need for something similar to a proof.

Difficult issues, unsolved or partially solved, tend to come up repeatedly for further refinements. Nothing remarkable about this. Not to be characterized as belaboring. AG

 

Science does not prove its conclusions.

What it does is GUESS at physical laws. This is what Feynman stated in The Character of Physical Law, and I totally agree. A good guess predicts what we observe. I don't see why you think I require mathematical proofs. Occasionally we get something like a mathematical proof, e.g., when Einstein derived the LT based on the assumption of the invariance of the SoL. But this is an exception. AG 

[Alan Grayson]

On Thursday, October 3, 2019 at 3:45:41 AM UTC-6, Lawrence Crowell wrote:

On Wednesday, October 2, 2019 at 7:31:56 PM UTC-5, Bruce wrote:

On Thu, Oct 3, 2019 at 10:14 AM Lawrence Crowell <goldenfield...@gmail.com> wrote:

On Wednesday, October 2, 2019 at 6:41:32 PM UTC-5, Bruce wrote:

On Thu, Oct 3, 2019 at 9:21 AM Lawrence Crowell <goldenfield...@gmail.com> wrote:

On Wednesday, October 2, 2019 at 5:46:50 PM UTC-5, Bruce wrote:

On Thu, Oct 3, 2019 at 3:03 AM Alan Grayson <agrays...@gmail.com> wrote:

In this case I was just responding to Bruce's certainty that inflation is mostly a red herring. I highly respect his opinions, but in this case, based on my study of this particular issue, I disagree. I am open to being proved wrong, but insults don't cut it. At least you agree that inflation does explain homogeneity. Aren't you curious about Bruce's take on this particular issue? AG

Inflation can result in an increase in flatness and homogeneity. But that is relevant only if flatness and homogeneity were problems in need of explanation.

Bruce 

The real problem is how did disparate regions of the universe become uniform when there would have been no causal connection between them. In particular with homogeneity inflation provides a mechanism whereby deviations from homogeneity and isotropy are uniform.

Fine. Provided they were not uniform at the start. It is all a matter of distributions and in initial conditions. And you know nothing about either, so why solve a problem before you know it exists? Besides, can you achieve thermal equilibrium in a non-equilibrium state in 10^{-35} sec?

Bruce 

Inflation started on a fiducial at 10^{-36}sec and lasted until 10^{-32} sec. Since the particle fields were near the Planck scale in energy this inflationary cycle lasted some 10^{10} times the periodicities of fields. That is enough to approximately have thermal equilibrium.

The problem is not the periodicity of the fields. The problem is the uniformity of the initial conditions. As Sabine points out, inflation just replaces one set of unknown initial conditions with another.

I would also take issue with her suggestion that inflation solves some problems with the origin of the fluctuations seen in the CMB. Inflation might provide a framework, but it does not provide an explanation for these fluctuations. The fluctuations are built in by hand, and the gaussian nature of the fluctuations is also built in by hand. So these features of the CMB are not "explained" by inflation in any sense at all. There gaussian nature, and the relative magnitude of 10^{-5} are both free parameters that are set by hand.

The initial conditions, what ever they were, were flattened out though by inflation. The anisotropy in the CMB is due to details in the field configuration of the scalar field. The theory just provides the action S = ∫d^4x√g(φR + L(φ)), but not the explicit initial conditions or the configuration of the field at reheating. The point though is these details were exponentially attenuated by inflation so their magnitude is small. Estimates of this works out pretty well.

LC

I have a different model. Inflation didn't attentuate the initial condition. Rather it preserved an initial condition of virtually perfect uniformity, which was about the one part in 100,000 observed in the CMBR. Before inflation began, the universe was tiny, say much less than the diameter of a proton. It was so small in comparison to the SoL, that it was in thermo equilbrium before inflation began. The sudden huge expansion preserved the already existing thermo equilibrium. If inflation didn't happen, the time of recombination would have occurred much later than 380,000 years after the BB, and by that time the original very tiny fluctuations would have increased, resulting in relatively large variations in the CMBR, much more than one part in 100,000. What I haven't calculated -- because I don't know how -- is whether the time duration before inflation was long enough, despite the large SoL, for the universe to reach an approximate thermo equilbrium of one part in 100,000. AG

[Lawrence Crowell]

On Thursday, October 3, 2019 at 7:59:51 AM UTC-5, Alan Grayson wrote:

On Thursday, October 3, 2019 at 3:45:41 AM UTC-6, Lawrence Crowell wrote:

On Wednesday, October 2, 2019 at 7:31:56 PM UTC-5, Bruce wrote:

On Thu, Oct 3, 2019 at 10:14 AM Lawrence Crowell <goldenfield...@gmail.com> wrote:

On Wednesday, October 2, 2019 at 6:41:32 PM UTC-5, Bruce wrote:

On Thu, Oct 3, 2019 at 9:21 AM Lawrence Crowell <goldenfield...@gmail.com> wrote:

On Wednesday, October 2, 2019 at 5:46:50 PM UTC-5, Bruce wrote:

On Thu, Oct 3, 2019 at 3:03 AM Alan Grayson <agrays...@gmail.com> wrote:

In this case I was just responding to Bruce's certainty that inflation is mostly a red herring. I highly respect his opinions, but in this case, based on my study of this particular issue, I disagree. I am open to being proved wrong, but insults don't cut it. At least you agree that inflation does explain homogeneity. Aren't you curious about Bruce's take on this particular issue? AG

Inflation can result in an increase in flatness and homogeneity. But that is relevant only if flatness and homogeneity were problems in need of explanation.

Bruce 

The real problem is how did disparate regions of the universe become uniform when there would have been no causal connection between them. In particular with homogeneity inflation provides a mechanism whereby deviations from homogeneity and isotropy are uniform.

Fine. Provided they were not uniform at the start. It is all a matter of distributions and in initial conditions. And you know nothing about either, so why solve a problem before you know it exists? Besides, can you achieve thermal equilibrium in a non-equilibrium state in 10^{-35} sec?

Bruce 

Inflation started on a fiducial at 10^{-36}sec and lasted until 10^{-32} sec. Since the particle fields were near the Planck scale in energy this inflationary cycle lasted some 10^{10} times the periodicities of fields. That is enough to approximately have thermal equilibrium.

The problem is not the periodicity of the fields. The problem is the uniformity of the initial conditions. As Sabine points out, inflation just replaces one set of unknown initial conditions with another.

I would also take issue with her suggestion that inflation solves some problems with the origin of the fluctuations seen in the CMB. Inflation might provide a framework, but it does not provide an explanation for these fluctuations. The fluctuations are built in by hand, and the gaussian nature of the fluctuations is also built in by hand. So these features of the CMB are not "explained" by inflation in any sense at all. There gaussian nature, and the relative magnitude of 10^{-5} are both free parameters that are set by hand.

The initial conditions, what ever they were, were flattened out though by inflation. The anisotropy in the CMB is due to details in the field configuration of the scalar field. The theory just provides the action S = ∫d^4x√g(φR + L(φ)), but not the explicit initial conditions or the configuration of the field at reheating. The point though is these details were exponentially attenuated by inflation so their magnitude is small. Estimates of this works out pretty well.

LC

I have a different model. Inflation didn't attentuate the initial condition. Rather it preserved an initial condition of virtually perfect uniformity, which was about the one part in 100,000 observed in the CMBR. Before inflation began, the universe was tiny, say much less than the diameter of a proton. It was so small in comparison to the SoL, that it was in thermo equilbrium before inflation began. The sudden huge expansion preserved the already existing thermo equilibrium. If inflation didn't happen, the time of recombination would have occurred much later than 380,000 years after the BB, and by that time the original very tiny fluctuations would have increased, resulting in relatively large variations in the CMBR, much more than one part in 100,000. What I haven't calculated -- because I don't know how -- is whether the time duration before inflation was long enough, despite the large SoL, for the universe to reach an approximate thermo equilbrium of one part in 100,000. AG

For various reasons this will not work. With inflation the cosmological horizon was 10^{-27}m in radius. The real problem is that without inflation winding back the cosmic time leads to nonsensical conditions.

LC

[Alan Grayson]

On Thursday, October 3, 2019 at 4:22:20 PM UTC-6, Lawrence Crowell wrote:

On Thursday, October 3, 2019 at 7:59:51 AM UTC-5, Alan Grayson wrote:

On Thursday, October 3, 2019 at 3:45:41 AM UTC-6, Lawrence Crowell wrote:

On Wednesday, October 2, 2019 at 7:31:56 PM UTC-5, Bruce wrote:

On Thu, Oct 3, 2019 at 10:14 AM Lawrence Crowell <goldenfield...@gmail.com> wrote:

On Wednesday, October 2, 2019 at 6:41:32 PM UTC-5, Bruce wrote:

On Thu, Oct 3, 2019 at 9:21 AM Lawrence Crowell <goldenfield...@gmail.com> wrote:

On Wednesday, October 2, 2019 at 5:46:50 PM UTC-5, Bruce wrote:

On Thu, Oct 3, 2019 at 3:03 AM Alan Grayson <agrays...@gmail.com> wrote:

In this case I was just responding to Bruce's certainty that inflation is mostly a red herring. I highly respect his opinions, but in this case, based on my study of this particular issue, I disagree. I am open to being proved wrong, but insults don't cut it. At least you agree that inflation does explain homogeneity. Aren't you curious about Bruce's take on this particular issue? AG

Inflation can result in an increase in flatness and homogeneity. But that is relevant only if flatness and homogeneity were problems in need of explanation.

Bruce 

The real problem is how did disparate regions of the universe become uniform when there would have been no causal connection between them. In particular with homogeneity inflation provides a mechanism whereby deviations from homogeneity and isotropy are uniform.

Fine. Provided they were not uniform at the start. It is all a matter of distributions and in initial conditions. And you know nothing about either, so why solve a problem before you know it exists? Besides, can you achieve thermal equilibrium in a non-equilibrium state in 10^{-35} sec?

Bruce 

Inflation started on a fiducial at 10^{-36}sec and lasted until 10^{-32} sec. Since the particle fields were near the Planck scale in energy this inflationary cycle lasted some 10^{10} times the periodicities of fields. That is enough to approximately have thermal equilibrium.

The problem is not the periodicity of the fields. The problem is the uniformity of the initial conditions. As Sabine points out, inflation just replaces one set of unknown initial conditions with another.

I would also take issue with her suggestion that inflation solves some problems with the origin of the fluctuations seen in the CMB. Inflation might provide a framework, but it does not provide an explanation for these fluctuations. The fluctuations are built in by hand, and the gaussian nature of the fluctuations is also built in by hand. So these features of the CMB are not "explained" by inflation in any sense at all. There gaussian nature, and the relative magnitude of 10^{-5} are both free parameters that are set by hand.

The initial conditions, what ever they were, were flattened out though by inflation. The anisotropy in the CMB is due to details in the field configuration of the scalar field. The theory just provides the action S = ∫d^4x√g(φR + L(φ)), but not the explicit initial conditions or the configuration of the field at reheating. The point though is these details were exponentially attenuated by inflation so their magnitude is small. Estimates of this works out pretty well.

LC

I have a different model. Inflation didn't attentuate the initial condition. Rather it preserved an initial condition of virtually perfect uniformity, which was about the one part in 100,000 observed in the CMBR. Before inflation began, the universe was tiny, say much less than the diameter of a proton. It was so small in comparison to the SoL, that it was in thermo equilbrium before inflation began. The sudden huge expansion preserved the already existing thermo equilibrium. If inflation didn't happen, the time of recombination would have occurred much later than 380,000 years after the BB, and by that time the original very tiny fluctuations would have increased, resulting in relatively large variations in the CMBR, much more than one part in 100,000. What I haven't calculated -- because I don't know how -- is whether the time duration before inflation was long enough, despite the large SoL, for the universe to reach an approximate thermo equilbrium of one part in 100,000. AG

For various reasons this will not work. With inflation the cosmological horizon was 10^{-27}m in radius. The real problem is that without inflation winding back the cosmic time leads to nonsensical conditions.

LC

Why won't it work? What are the nonsensical conditions when the clock is reversed? I didn't claim there is no inflation, so what have the nonsensical conditions have to do with anything I wrote? AG 

[Alan Grayson]

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 

[Bruce Kellett]

On Fri, Oct 4, 2019 at 9:54 AM Alan Grayson <agrays...@gmail.com> 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

[Alan Grayson]

I think you're agreeing that the model I posit, makes sense; namely, that inflation preserves the original thermo equilibrium, and this is important since without inflation the tiny fluctuations would have increased, the CMBR would have occurred much later, and departures from one part in 100,000 would be manifested. AG 

[Lawrence Crowell]

In order to explain it fully would require pumping out a fair amount of general relativity stuff. I am not going there right now --- too tired. If what you say were to work it would have already been proposed and accepted.

LC

[Lawrence Crowell]

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

[Lawrence Crowell]

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 <agrays...@gmail.com> 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

[Alan Grayson]

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 

[Lawrence Crowell]

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. 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 

[Philip Thrift]

The new tech way: deep nets for deep space.

https://bids.berkeley.edu/events/physics-machine-learning-workshop

This workshop focused on substantive connections between machine learning (including but not limited to deep learning) and physics (including astrophysics). Namely, we are interested in topics like imbuing physical laws into training (e.g., physics regularization of layers), learning new physical phenomena from learned models, physics-constrained reinforcement learning, prediction outside training parameters, causal inference, and the (physical) interpretability of models. 

@philipthrift

[Alan Grayson]

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 <agrays...@gmail.com> 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

[Lawrence Crowell]

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 <agrays...@gmail.com> 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

[Alan Grayson]

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 <agrays...@gmail.com> 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 

[John Clark]

On Thu, Oct 3, 2019 at 7:54 PM Alan Grayson <agrays...@gmail.com> 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 

The more fine tuned the initial conditions of the Universe needs to be for a theory to explain what we see today the less credible it is, that's why I can't take Superdeterminism seriously; the Big Bang without Inflation is not quite as bad as Superdeterminism in that regard but it's pretty damn bad. The density of matter and energy in the universe needs to be one specific value for the spacetime curvature of the universe to be flat at the largest cosmological level, and today we know it is within less than 0.4% of that critical value and that's the margin of error. That critical value gets less as time goes on so in the very early universe it must have departed from that critical value by less than one part in 10^62, and yet there is no theoretical reason it couldn't have been any value at all. That's fine tuning with a vengeance!

Inflation theory proposes a mechanism for the Universe to undergo a phase change when it was 10^-36 seconds old that resulted in the expansion dramatically speeding up at a exponential rate, in this case every 10^-37 seconds the linear distance would double in size and of course the volume would get 8 times larger. Nobody knows how many times it doubled but if it doubled just 330 times the linear distance would have increased by a factor of 10^100 in just 3.3 10^-35 seconds; current thinking is it expanded by AT LEAST a factor of 10^78 and probably much more. If this is true then even if the universe was very highly curved before 10^-36 seconds the inflation would have flattened out that curvature to the undetectable levels we see today.   

   

Inflation also explains why when we look at a map of the Cosmic Microwave Background Radiation we see the universe as it was when it was 380,000 years old but even then it was 900,000 light years across, and yet the difference in temperature from the deepest red to the deepest blue on that map differs from 2.726 Kelvin by less than one part in a hundred thousand. 

Inflation even explains why we don't see any Magnetic Monopoles which most particle theories say should be stable and should have been produced in abundance in the very early universe; inflation diluted them so much that now they are super rare.   

John K Clark

[Lawrence Crowell]

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 <agrays...@gmail.com> 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

[Alan Grayson]

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 

[Lawrence Crowell]

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

[Alan Grayson]

It's the "ironed out" that I don't understand. If there were some fluctuations, small deviations from thermal equilibrium, why would a sudden expansion attenuate them? It makes more sense to me that the universe was already very close to thermal equilibrium during inflation, and inflation preserved this state. BTW, I am not "belaboring" anything here; rather, I am trying to resolve, or possibly modify, a key element of the inflation model. AG

[Lawrence Crowell]

On Saturday, October 5, 2019 at 11:41:25 AM UTC-5, Alan Grayson wrote:

On Saturday, October 5, 2019 at 7:57:59 AM UTC-6, Lawrence Crowell wrote:

They came to equilibrium, and what thermal fluctuations that deviated away from equilibrium were "ironed out" by inflation.

It's the "ironed out" that I don't understand. If there were some fluctuations, small deviations from thermal equilibrium, why would a sudden expansion attenuate them? It makes more sense to me that the universe was already very close to thermal equilibrium during inflation, and inflation preserved this state. BTW, I am not "belaboring" anything here; rather, I am trying to resolve, or possibly modify, a key element of the inflation model. AG

This is why these post with you drive me nuts. It is for the same reason that if waves are stretched out they are made more IR. If clumps are stretched out, think hard speed bump vs a soft one that is spread out, or if curvatures are stretched these occur on a low energy or larger scale.

LC

[John Clark]

On Sat, Oct 5, 2019 at 12:41 PM Alan Grayson <agrays...@gmail.com> wrote:

> It's the "ironed out" that I don't understand. If there were some fluctuations, small deviations from thermal equilibrium, why would a sudden expansion attenuate them? 

As I explained in my previous post, Inflation Theory says a very very very small part of the pre-inflationary universe would have had time to reach thermal equilibrium, and that small part then underwent exponential expansion and become 10^100 times larger (or maybe "only" 10^78 times larger) in just 10^-35 seconds. And that very very small part is our entire observable universe. And that very very very small part of the Universe is still in thermal equilibrium, or close to it.

> It makes more sense to me that the universe was already very close to thermal equilibrium during inflation, 

As I also explain in my previous post, there is no theoretical reason to expect the pre-inflationary universe to be anywhere even close to thermal equilibrium, and the less fine tuning of initial conditions that a theory needs to match current observations, that is to say the less often you have to say "that's just the way it is", the better. 

By the way, this thread is quickly becoming unreadable, your post had 12 iterations of quotes, that's quotes of quotes of quotes of quotes of quotes of quotes of quotes of quotes of quotes of quotes of quotes of quotes. 

John K Clark

[Lawrence Crowell]

Based on the theory of quantum fields and thermodynamics in curved spacetime there is every reason to think the system was not in equilibrium. Also the initial state of the universe was very clearly extremely low entropic and so likely not in equilibrium.

As these posts grow in numbers of responses I generally drop them. They become difficult to follow and after they reach 100 the list is partitioned in ways that make it even harder. 

LC 

[Alan Grayson]

On Saturday, October 5, 2019 at 1:27:49 PM UTC-6, Lawrence Crowell wrote:

On Saturday, October 5, 2019 at 11:41:25 AM UTC-5, Alan Grayson wrote:

On Saturday, October 5, 2019 at 7:57:59 AM UTC-6, Lawrence Crowell wrote:

They came to equilibrium, and what thermal fluctuations that deviated away from equilibrium were "ironed out" by inflation.

It's the "ironed out" that I don't understand. If there were some fluctuations, small deviations from thermal equilibrium, why would a sudden expansion attenuate them? It makes more sense to me that the universe was already very close to thermal equilibrium during inflation, and inflation preserved this state. BTW, I am not "belaboring" anything here; rather, I am trying to resolve, or possibly modify, a key element of the inflation model. AG

This is why these post with you drive me nuts. It is for the same reason that if waves are stretched out they are made more IR. If clumps are stretched out, think hard speed bump vs a soft one that is spread out, or if curvatures are stretched these occur on a low energy or larger scale.

LC

Bruce has a dim view of inflation theory. He says it's a solution seeking a problem. He doesn't say, but if it's related to the present large scale homogeneity of the observable universe, it raises the issue of whether, just before or during inflation, the universe was already in thermal equiibrium. It's a reasonable question because, throughout that time, the universe was extraordinarily tiny and in causally connected. What's lacking in your reply, and possibly in the theory supporting inflation ON THIS PARTICULAR ISSUE, is a rigorous definition of thermal equilibrium, and whether the time scale of inflation (its duration), the size of the universe during that time, and the SoL, whether thermal equilibrium is definitely ruled OUT. Maybe it deviated by just one part in 100,000 and this is what is measured in the CMBR. If the question drives you nuts, it's probably because, to some extent, you share the world-view of the ruling elite in ancient Greece who found the questions of Socrates intolerable and insisted he drink the hemlock. My method is to test the claims of theories, and the more polemic the answers, the less confidence I have in their truth value.  That said, I thank you for the plausible information that particles became manifest with the decay of the original vacuum. AG

[Alan Grayson]

On Sunday, October 6, 2019 at 4:46:59 AM UTC-6, John Clark wrote:

On Sat, Oct 5, 2019 at 12:41 PM Alan Grayson <agrays...@gmail.com> wrote:

> It's the "ironed out" that I don't understand. If there were some fluctuations, small deviations from thermal equilibrium, why would a sudden expansion attenuate them? 

As I explained in my previous post, Inflation Theory says a very very very small part of the pre-inflationary universe would have had time to reach thermal equilibrium, and that small part then underwent exponential expansion and become 10^100 times larger (or maybe "only" 10^78 times larger) in just 10^-35 seconds. And that very very small part is our entire observable universe. And that very very very small part of the Universe is still in thermal equilibrium, or close to it.

> It makes more sense to me that the universe was already very close to thermal equilibrium during inflation, 

As I also explain in my previous post, there is no theoretical reason to expect the pre-inflationary universe to be anywhere even close to thermal equilibrium, and the less fine tuning of initial conditions that a theory needs to match current observations, that is to say the less often you have to say "that's just the way it is", the better. 

If the pre-inflation universe was a vacuum in the absence of particles, I don't think thermal equilibrium applies to it. This is not fine tuning AFAICT. OTOH, for the reasons outlined in my last post to LC, the parameters such as the SoL, the size of the universe during inflation, and the fact that it was causally connected throughout, suggests that thermal equilibrium DURING inflation is a possibility which must be considered. AG 

By the way, this thread is quickly becoming unreadable, your post had 12 iterations of quotes, that's quotes of quotes of quotes of quotes of quotes of quotes of quotes of quotes of quotes of quotes of quotes of quotes. 

I don't understand the basis for your complaint. This thread is relatively short, much shorter than other threads you have been active on, and without any complaints as above. AG 

John K Clark

[Lawrence Crowell]

On Sunday, October 6, 2019 at 2:50:51 PM UTC-5, Alan Grayson wrote:

On Saturday, October 5, 2019 at 1:27:49 PM UTC-6, Lawrence Crowell wrote:

On Saturday, October 5, 2019 at 11:41:25 AM UTC-5, Alan Grayson wrote:

On Saturday, October 5, 2019 at 7:57:59 AM UTC-6, Lawrence Crowell wrote:

They came to equilibrium, and what thermal fluctuations that deviated away from equilibrium were "ironed out" by inflation.

It's the "ironed out" that I don't understand. If there were some fluctuations, small deviations from thermal equilibrium, why would a sudden expansion attenuate them? It makes more sense to me that the universe was already very close to thermal equilibrium during inflation, and inflation preserved this state. BTW, I am not "belaboring" anything here; rather, I am trying to resolve, or possibly modify, a key element of the inflation model. AG

This is why these post with you drive me nuts. It is for the same reason that if waves are stretched out they are made more IR. If clumps are stretched out, think hard speed bump vs a soft one that is spread out, or if curvatures are stretched these occur on a low energy or larger scale.

LC

Bruce has a dim view of inflation theory. He says it's a solution seeking a problem. He doesn't say, but if it's related to the present large scale homogeneity of the observable universe, it raises the issue of whether, just before or during inflation, the universe was already in thermal equiibrium. It's a reasonable question because, throughout that time, the universe was extraordinarily tiny and in causally connected. What's lacking in your reply, and possibly in the theory supporting inflation ON THIS PARTICULAR ISSUE, is a rigorous definition of thermal equilibrium, and whether the time scale of inflation (its duration), the size of the universe during that time, and the SoL, whether thermal equilibrium is definitely ruled OUT. Maybe it deviated by just one part in 100,000 and this is what is measured in the CMBR. If the question drives you nuts, it's probably because, to some extent, you share the world-view of the ruling elite in ancient Greece who found the questions of Socrates intolerable and insisted he drink the hemlock. My method is to test the claims of theories, and the more polemic the answers, the less confidence I have in their truth value.  That said, I thank you for the plausible information that particles became manifest with the decay of the original vacuum. AG

These questions by you drive me crazy because they go around and around. 

Bruce is very conservative, too conservative I think. Inflation makes some sense out of things, and while it is not a fundamental theory, it does push ignorance back. It also has some measure of observational support. 

LC

[Alan Grayson]

It's your problem, not mine; sort of an intolerance for detailed dialogue on deep and confusing issues. AG 

Bruce is very conservative, too conservative I think. Inflation makes some sense out of things, and while it is not a fundamental theory, it does push ignorance back. It also has some measure of observational support. 

I agree with inflation wrt the flatness problem. Not sure exactly which part of inflation Bruce finds questionable. AG 

LC