Different symmetries or no symmetries in string theory?

[Suekdccia]

TL;DR

Does string theory permit fundamental symmetries to change between universes?

I was reading the book "A Fortunate Universe" by Geraint Lewis and Luke Barnes and something caught my attention:

At page 195 the authors say that universes with different symmetries could be modeled and they would have dramatic results like having different conservation laws.

I asked Mr. Lewis if he could give me more information about this and he told me this:

"We can play with equations and add or subtract dimensions in our universe – like adding another time dimension to relativity. These other hypothetical universes could have different symmetries, so things like electric charge might not be conserved, while kinetic energy is. This would give very different physical outcomes. And yes, we could get very different physical laws with interactions that we just don’t see in our universe"

He mentioned that these universes with different symmetries and non-conserved quantities would be the result of "playing" with the dimensions of mathematical models of universes. This reminds me a lot to what happens in String Theory compactification or in M Theory. And also, at another book by Kurt Sundermeyer called "Symmetries in Fundamental Physics", he says at page 466:

"It is an astounding state of affairs that string theories in 10 dimensions vibrate with symmetries, but that after compactification we may get into worlds with no symmetries at all"

I have always read that in string theory landscape the different vacua would have the same symmetries but they would be broken differently, or at least that is what I have understood until now. But I have never read anything about vacua with different fundamental symmetries in string theory.

Therefore, does String Theory or M Theory propose that these universes with very different fundamental symmetries may exist? Do any of these theories speculate that universes with different kinds of symmetries (different global symmetries, local symmetries, gauge symmetries...etc) may exist?

 

[CallMeDirac]

Summary:: Does string theory permit fundamental symmetries to change between universes?

I was reading the book "A Fortunate Universe" by Geraint Lewis and Luke Barnes and something caught my attention:

At page 195 the authors say that universes with different symmetries could be modeled and they would have dramatic results like having different conservation laws.

I asked Mr. Lewis if he could give me more information about this and he told me this:

"We can play with equations and add or subtract dimensions in our universe – like adding another time dimension to relativity. These other hypothetical universes could have different symmetries, so things like electric charge might not be conserved, while kinetic energy is. This would give very different physical outcomes. And yes, we could get very different physical laws with interactions that we just don’t see in our universe"

He mentioned that these universes with different symmetries and non-conserved quantities would be the result of "playing" with the dimensions of mathematical models of universes. This reminds me a lot to what happens in String Theory compactification or in M Theory.And also, at another book by Kurt Sundermeyer called "Symmetries in Fundamental Physics", he says at page 466:

"It is an astounding state of affairs that string theories in 10 dimensions vibrate with symmetries, but that after compactification we may get into worlds with no symmetries at all"

I have always read that in string theory landscape the different vacua would have the same symmetries but they would be broken differently, or at least that is what I have understood until now. But I have never read anything about vacua with different fundamental symmetries in string theory.

Therefore, does String Theory or M Theory propose that these universes with very different fundamental symmetries may exist? Do any of these theories speculate that universes with different kinds of symmetries (different global symmetries, local symmetries, gauge symmetries...etc) may exist?

Things like bubble theory and string theory do propose different symmetries but I am unsure about M theory.

 

[Suekdccia]

Things like bubble theory and string theory do propose different symmetries but I am unsure about M theory.

What is bubble theory? Cosmological inflation?

But if these propose that vacua would have different symmetries, wouldn't that mean that they woulf be governed by different fundamental laws of physics?

 

[CallMeDirac]

What is bubble theory? Cosmological inflation?

But if these propose that vacua would have different symmetries, wouldn't that mean that they woulf be governed by different fundamental laws of physics?

Yes, each bubble is its own universe and is dictated by its own laws of physics.

 

[Suekdccia]

But the thing is that in string theory, as far as I understand it, different vacua would have different laws of low-energy physics while the laws at high energies would all stay the same. If the fundamental symmetries would change between vacua (therefore showing different conservation laws for example, as Geraint Lewis told me) wouldn't that mean that the very fundamental laws of high energy physics would also change?