Vacuum energy density after inflation

  • #1
285
22
Its said that if there are different pocket universes made by inflation then this solves the alleged fine tuning of dark energy. My question is this: can the idea of different values for the vacuum energy density in these different pockets be derived from quantum field theory or does it need something more exotic like string theory?
 

Answers and Replies

  • #2
Chronos
Science Advisor
Gold Member
11,408
742
Multiverse to the rescue again! It's the undisputed king of patent medicine curing everything from initial conditions to fine tuning, anthropism, the values of dimensionless constants and even falsification of TOE's..
 
  • Like
Likes fresh_42
  • #3
Haelfix
Science Advisor
1,955
222
My question is this: can the idea of different values for the vacuum energy density in these different pockets be derived from quantum field theory or does it need something more exotic like string theory?
Field theory alone. All you need is a fundamental scalar with a metastable potential, which undergoes vacuum decay. The ensuing physics could (depending on the details of the new ground state) have radically different properties.
 
  • Like
Likes windy miller
  • #4
285
22
Field theory alone. All you need is a fundamental scalar with a metastable potential, which undergoes vacuum decay. The ensuing physics could (depending on the details of the new ground state) have radically different properties.
Thanks, and those radically different properties you mention would they apply to just the vacuum energy density or to other values in physics? I believe that things like the masses of would only differ from pocket univers to pocket universe if string theory or something like it were true. Is that correct or incorrect?
 
  • #5
Haelfix
Science Advisor
1,955
222
In principle after vacuum decay, the behaviour of many of the constants in nature could be altered. It's a tiny bit involved, but a fundamental scalar could couple, almost like the interaction of the Higgs field does. The latter contributes to both gauge bosons, as well as fermions, so many properties of the surrounding universe would be radically different, depending on the details of the new vacuum.

String theory is something else, although a similar mechanism could exist within that framework as well. Many of the stringy models produce lots of new scalar fields (called Moduli), and the same sort of thing in principle could happen there.

The sketch of the phenomenon is really quite simple to describe mathematically, and similar things happen all over physics (for instance in condensed matter systems undergoing phase transitions) which is why its not completely crazy, and the details are very closely tied in with the mathematics of inflation.
 
  • Like
Likes windy miller

Related Threads on Vacuum energy density after inflation

Replies
10
Views
2K
  • Last Post
Replies
18
Views
4K
Replies
1
Views
882
Replies
29
Views
2K
  • Last Post
2
Replies
25
Views
5K
  • Last Post
Replies
4
Views
2K
Replies
2
Views
578
Replies
7
Views
786
  • Last Post
Replies
7
Views
748
Replies
0
Views
2K
Top