B Looking to get a better understanding of bubble universe formation

[Lynch101]

TL;DR

Are the values of the universal constants statistically independent of the initial conditions of a bubble universe?

I'm trying to get a somewhat better understanding of the implications of String Theory, eternal inflation, and the multiverse (from a layman's perspective).

I was wondering, which of the following analogies (if either ) would be more suitable for describing how bubble universes are formed and how the values of the universal constants are set, would it be:

1) Like a slot machine, where the slot machine is first built and then the values are set randomly afterwards.

or 2) like a bingo drum, where each ball represents a universe with different values for the constants and each one is drawn randomly?

Hopefully this makes sense to someone.

 

[Lynch101]

Apologies, let me try that again. I posted it just before going to bed so perhaps didn't articulate it in the best possible way. Admittedly, I don't have a deep understanding of all the concepts referenced below, but hopefully it makes a bit more sense.

In the context of eternal inflation coupled to the string landscape, the formation of pocket (bubble) universes involves Coleman–De Luccia (CDL) tunneling (is that correct) from a parent false-vacuum region into one of the many metastable vacua (referred to as the string landscape?).

Each of these vacua corresponds to a distinct low-energy effective field theory, with different values of coupling constants, particle masses, and the cosmological constant. Alan Guth described the process as follows (source: transcribed from Phil Halper Interview):
“String theory predicts that there's not just one kind of vacuum rather there's a huge number of different kinds of vacuum. In string theory string theorists talk about numbers like perhaps 10 to the 500 or even larger. If that’s the case it seems very plausible then each of these different types of vacuum would have their own low energy local physics. The physics around us is basically the physics of small changes around the vacuum state that we're basically living in, so when one of these pocket universes forms it would essentially randomly choose one type of vacuum. It would be influenced by where it came from but it would be somewhat of a random choice what type of vacuum would appear inside the pocket universe...”

This seems to raise an ontological question, which is what my analogies above were trying to get at:
Is the vacuum state (and thus the low-energy constants) instantiated at the moment of bubble nucleation as part of the CDL instanton solution — i.e., each tunneling event targets a specific landscape minimum from the outset — or does the bubble form as a geometrically defined region first, with the vacuum state forming subsequently?

In other words:

• Option A: bubble nucleates as an “empty” expanding domain, and only afterward does the scalar field stochastically settle into one of the landscape minima.
• Option B: The CDL instanton is a trajectory from false vacuum to a specific true vacuum minimum; the bubble is born already in that vacuum.

In terms of the analogies

1. Option A: Like a slot machine, where the slot machine is first built and then the values are set randomly afterwards.
2. like a bingo drum, where each ball represents a potential universe/vacuum with different values for the constants and each one is drawn randomly?

 

[PeterDonis]

Is the vacuum state (and thus the low-energy constants) instantiated at the moment of bubble nucleation as part of the CDL instanton solution — i.e., each tunneling event targets a specific landscape minimum from the outset — or does the bubble form as a geometrically defined region first, with the vacuum state forming subsequently?

You need to actually look at some references and see if they describe the process in a way that matches one or the other of your claimed possibilities--or if they describe something that is neither one.

From what you quoted from the interview transcript, right now my bet is on "neither one". But you really need to be looking at actual papers and spending some time understanding the models they propose, and then asking questions based on what you find there. An interview transcript is just not going to get you to where you want to go on a topic like this.

 

[PeterDonis]

And by the way, @Lynch101, this is an "A" level topic (and arguably might belong in the Beyond the Standard Models forum). It might be discussible to some extent at the "I" level. But I'm not sure anything useful can be said about it at the "B" level, which is where you put this thread. (And you definitely should not be trying to make up analogies without a firm grounding in the topic from actual papers.)

Given that, I am closing this thread. If you want to start a new thread on this general topic, please find an actual paper to use as a reference and base your question on what you read there. And please expect the thread level to be changed to "A" if you don't set it there yourself.