It is often said that low energy/effective physical laws (i.e fundamental physical constants) could possibly change if a quantum false vacuum decays into a true (stable) level of quantum vacuum.

But, could truly fundamental principles change? Could we have an extremely large transition of quantum vacuum levels that would cause fundamentally different (high-energy) laws and principles to appear?

PS: I found a paper that says

(...) This bubble will grow until at some point another bubble nucleates within it, or another bubble nucleates somewhere in the parent universe. This process will go on, and since there will be no limit to the size of the original universe, it can grow indefinitely, probably harbouring an infinite number of smaller pocket universes. The boundaries between these pockets will consist of domain walls, where the vacuum takes on intermediate values between the parents and the daughters value. Passing such a domain wall would be impossible for an observer, since it would have to travel to a universe with completely different laws of physics, making observing or even existing impossible


I'm not sure if it is referring to a radical change of fundamental laws and principles of nature


closed as primarily opinion-based by John Rennie, ZeroTheHero, Jon Custer, Kyle Kanos, Norbert Schuch Jan 6 at 0:39

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    $\begingroup$ Referring to the quoted paper, not to OP: is there someone here who thinks that is physics? $\endgroup$ – Elio Fabri Dec 22 '18 at 15:39
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    $\begingroup$ @ElioFabri This paper is motivated by the problems in understanding cosmic inflation and dark energy. Is it highly speculative? Yes. Is it physics? Yes, if you believe that the subjects of inflation and dark energy are physics. $\endgroup$ – Lewis Miller Dec 22 '18 at 16:44
  • $\begingroup$ "Completely different laws of physics" is an exaggeration. Presumably it would not cover spacetime becoming a discrete lattice or quantum mechanics no longer being applicable. What is meant in the literature is usually more like coupling constants and the symmetry breaking of different parameters. $\endgroup$ – Anders Sandberg Dec 22 '18 at 20:28
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    $\begingroup$ A phrase such as "probably harbouring an infinite number of smaller pocket universes" has lost touch with correct scientific practice I think. I mean the care and determination not to fool oneself or others; the aim to keep in plain view the limits of ones own knowledge. The desire to keep in touch with empirical tests. $\endgroup$ – Andrew Steane Dec 22 '18 at 21:44
  • $\begingroup$ @AndersSandberg So, are you suggesting that to have (radically) fundamental different laws, space-time would have to be a lattice? Would this be like saying the universe (space time) would be basically a computer-like structure? Could we have even universes behaving under fundamentally different logic systems? Or even universes not obeying any logic (where even impossible things could happen, like having a straight line intersecting a circle in 3 points, or factorizing number 181...etc)? If yes, is it there any computer-universe or cellular automata model where all of this could happen? $\endgroup$ – Oni Ein Dec 23 '18 at 0:48

Could false quantum vacuum decay change fundamental laws of physics?

No, by definition of "fundamental laws of physics." If a physical process causes some laws to change, then those laws were never really fundamental. What can happen (and has happened) is that laws that we once considered to be fundamental turn out to be mere approximations that only work well in limited circumstances. Here's an anecdote to illustrate this:

  • Person $E$, who grew up on Earth, might consider "the acceleration of gravity is $9.8$ m/s$^2$" to be a fundamental physical constant.

  • Person $M$, who grew up on Mars, might consider "the acceleration of gravity is $3.7$ m/s$^2$" to be a fundamental physical constant.

If $E$ travels to mars, $E$ might declare that one of the fundamental physical constants has changed; but of course that's only because the thing that $E$ was calling a "fundamental physical constant" was never really fundamental. It was a consequence of more-fundamental laws, specialized for a particular situation.

Compared to the excerpt about domain-wall crossing, traveling from Earth to Mars might not be a drastic enough change to make human existence impossible, but the idea is similar.

It is often said that low energy/effective physical laws (i.e fundamental physical constants) could possibly change if a quantum false vacuum decays into a true (stable) level of quantum vacuum.

The key words here are "low energy/effective." The current Standard Model of particle physics is believed (for good reasons) to be only a low energy/effective model, and the desire to explore beyond the limits of this model is part of why physicists want to build more and more powerful particle accelerators. We don't currently know what the really fundamental laws are, and some things that currently appear to be fundamental physical constants might turn out to be situation-specific consequences of something even more fundamental.

The idea that our cosmological neighborhood might be in a metastable state that will eventually decay into a more stable state, changing the low-energy/effective laws that are currently expressed by the Standard Model, is speculative. The key message here is that even if that speculation turned out to be true, it would just be another (more extreme) example of what the Earth/Mars anecdote illustrated.

  • $\begingroup$ How could there be any "fondamental law" in the real Universe (or in the "Multiverse")? That concept doesn't make any sense to me. There can't be any "fundamental" laws at all. Wheeler's idea has more sense to me : "laws without laws". Strangely, each time I hear "fundamental laws", I scratch the walls with my nails! I have a similar feeling about "constants of nature". $\endgroup$ – Cham Dec 23 '18 at 1:10

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