A bigger structure than multiverse

[dhillonv10]

Hi all,

Recently there was a paper out by Susskind et. al on the topological phases of eternal inflation. We know of eternal inflation to populate our multiverse but in that paper Susskind talks about different kinds of eternal inflation, if one pays close attention to those words, does that imply that different eternal inflations we get different multiverses?? For a moment let's take the example of a bubble-bath, that's commonly used to explain the idea of the multiverse, so if one eternal inflation A filled the bath A' with everything (our multiverse) does that mean that a variation B of eternal inflation will fill a bath B' with everything? If so then what would this structure be called and is that the end? I remember watching this video on why there are 11 dimensions in M-theory and basically the core idea there was that when you get to counting up all 11 degrees of freedom, that's it, you've encompassed everything, there's nothing left to include so 11 would be all, could it be the same way for this postulated bigger structure of the multiverse?? I would really appreciate if someone can explain this to me in more detail, and as always links to papers and such as much appreciated.

 

[mitchell porter]

In that paper (1003.1347), they are examining how the inflating universe looks for different assumptions about how often the "white" vacuum state spontaneously turns into the "black" vacuum state. If the transition probability is low, you only ever get islands of "black" vacuum in a sea of "white"; if the transition probability is high, everything eventually turns to the "black" vacuum state; if it's somewhere in between, you get networks of black against a white background, or vice versa.

None of this is supposed to be very realistic. They say at the beginning of the paper that, in reality, there ought to be far more than two vacuum states. Also, the white-to-black transition probability ought to be determined by fundamental physics, it shouldn't be something that can actually take different values independent of fundamental theory. It's as if you knew there was a number $$\pi$$, that's the ratio of a circle's circumference to its diameter, but you don't know what is $$\pi$$'s actual value; but you nevertheless go ahead and work out what the facts of geometry would be if $$\pi$$ is less than 2, and what the facts of geometry would be if $$\pi$$ is greater than 4, and what the facts of geometry would be if $$\pi$$ is between 2 and 4. Only the last case is relevant to reality, but because you don't know that $$\pi$$ is actually 3.14..., you look at the other cases as well.

That is sort of what's happening here. They are looking at different models of the multiverse not knowing which of them is right - and quite possibly none of them are right and the whole idea is wrong.

 

[dhillonv10]

mitchell, I am working on an approach that can provide another look at how we analyze the behavior of white and black vaccua and of couse as you said the behaviors are based on some fundamental physical theory, do you think providing another interpretation is any good??

 

[mitchell porter]

You may as well state your ideas and see how people react to them; it's one of the few forms of experimental method directly available to theoretical physicists.