Varying laws of high energy physics in inflation?

[Suekdccia]

TL;DR Summary

Could different laws of high energy physics take place in cosmological inflationary models?

I am have some questions that have arisen while reading an old but interesting article by Andreas Albrecht [1] that cites an article by Andrei Linde in the 90s on cosmic inflation [2]...


Albrecht's paper is related to his ideas on "clock ambiguity" in which he proposes that the laws of physics (even the most fundamental ones) could have been different. On page 9-10, he says:


"Many different effective GUT scale theories could account for our observations of the physical world. If quantum cosmology actually forces us to consider a range of high energy physics models as equally realistic alternatives (as I argued in Sect. 2) then the implications for inflation could be very interesting"


So he cites a couple of Linde papers related to this topic, one of them being [2]. I am reading it and I have some important doubts:


1. I have always read that in inflationary models dealing with multiple universes, they would have different physical laws at low energies (low-energy laws of physics) but from what Albrecht says in his paper, could it also be possible that they could have different fundamental high energy laws of physics?* Does the paper of Linde [2] deal with this topic, as Albrecht seems to indicate when citing it?


2. If so, what conditions would have to be met for this to be possible? What would there have to be in the universe for it to be possible?

Of course since we cannot experimentally prove which inflationary model is right, if any, I am asking this question from a theoretical point of view

[1]: https://arxiv.org/abs/gr-qc/9408023

[2]: https://arxiv.org/abs/gr-qc/9306035

*I found another article by Linde (https://arxiv.org/abs/hep-th/0211048) where he suggests that in inflation theory one may consider that different universes or domains may have different fundamental laws of physics (see section 6, especially towards the end)

 

[PeterDonis]

I have always read

Where? Please give some references.

 

[PeterDonis]

in inflationary models dealing with multiple universes, they would have different physical laws at low energies (low-energy laws of physics) but from what Albrecht says in his paper, could it also be possible that they could have different fundamental high energy laws of physics?

I don't think the distinction you are making here is valid. Our current universe does not have "high energy laws of physics" and "low energy laws of physics". It just has laws of physics. What the papers you reference are describing as "high energy" and "low energy" laws are really just what kinds of behavior the single set of laws in our universe lead to for the different energy regimes.

For example, the Standard Model predicts that, above the electroweak symmetry breaking energy, the underlying masslessness of all of the Standard Model particles is manifest, whereas below the electroweak symmetry breaking energy, electroweak symmetry breaking makes most of the Standard Model fields behave as if they have nonzero rest mass due to interaction with the Higgs field. This is not two different sets of physical laws; it is just how the same set of physical laws lead to different behavior in different energy regimes. It's no different from a piece of ferromagnetic material having zero magnetization above the critical temperature but nonzero magnetization below the critical temperature (an example used in the first paper you reference). The laws of physics governing ferromagnetism don't change with temperature; only the observed behavior the laws lead to does.

 

[PeterDonis]

in inflation theory one may consider that different universes or domains may have different fundamental laws of physics

Per my previous post, I think this is really a misnomer. What Linde is actually describing is that a particular set of laws--basically the laws of an "eternal inflation" model--have multiple possible solutions, and those solutions correspond to different "universes" with different behaviors. This would mean that what we currently consider to be "the physical laws" of our universe are not actually laws, they are one particular solution of the actual laws (the "eternal inflation" laws Linde is describing).

 

[kimbyd]

Albrecht's paper is related to his ideas on "clock ambiguity" in which he proposes that the laws of physics (even the most fundamental ones) could have been different. On page 9-10, he says:


"Many different effective GUT scale theories could account for our observations of the physical world. If quantum cosmology actually forces us to consider a range of high energy physics models as equally realistic alternatives (as I argued in Sect. 2) then the implications for inflation could be very interesting"


So he cites a couple of Linde papers related to this topic, one of them being [2]. I am reading it and I have some important doubts:


1. I have always read that in inflationary models dealing with multiple universes, they would have different physical laws at low energies (low-energy laws of physics) but from what Albrecht says in his paper, could it also be possible that they could have different fundamental high energy laws of physics?* Does the paper of Linde [2] deal with this topic, as Albrecht seems to indicate when citing it?

What I believe he was trying to illustrate here is the difficulty in extrapolating from our observations to a theory of everything. He's saying, in effect, that you can take the exact same set of observations and match either Theory of Everything A with clock X, or instead match Theory of Everything B with clock Y. The A/X pair looks completely identical to the B/Y pair. So you could never, even in principle, distinguish between theories A and B.

The rest of the paper is an attempt to move forward despite this ambiguity.

So it's not really about varying laws of physics. It's about the difficulties in determining which proposed laws of physics are more or less likely to be true, in effect by limiting the range of inquiry to a range of cases where there is no such ambiguity.