Consequences of the absence of global symmetries...?

In summary, Lee Smolin argues that laws are not immutable and can change over time, even the most fundamental ones. This idea is related to his idea that there are no global symmetries in the universe, and that the universe could have arisen out of a hot early phase without any global symmetries.
  • #1
230
23
TL;DR Summary
Consequences of the absence of global symmetries...?
I found some interesting discussions in this site (e.g: https://www.physicsforums.com/threads/smolin-lessons-from-einsteins-discovery.849464/; https://www.physicsforums.com/threads/relatismo-to-the-max.83885/) which are related to Lee Smolin's ideas that laws are not immutable and can therefore change in time (even the most fundamental ones).
I've seen Smolin's idea about laws being able to change with time is related to his idea that there are no fundamental global symmetries (and therefore they are emergent or approximate, contrarily to what is believed by most physicists working in the "unification program" where one would expect to find more and more symmetry in higher energies) (https://www.physicsforums.com/threa...se-that-symmetries-are-emergent.995027/page-2).
Therefore, if the universe had no global symmetries would this mean that all laws of physics (even the most fundamental ones) and fundamental symmetries like the Lorentz or CPT invariances would not be fundamental and unchanging but rather emergent, approximate and with the potential to change in time (at least in a cosmological scale)?
 
Physics news on Phys.org
  • #2
Some laws are not a consequence of a symmetry. For example, the Newton equation ##m\ddot{x}=F(x)##.
 
  • #3
Demystifier said:
Some laws are not a consequence of a symmetry. For example, the Newton equation ##m\ddot{x}=F(x)##.
But the laws of Newton are not fundamental, but rather emergent. I was talking about the fundamental laws of physics
 
  • #4
Suekdccia said:
But the laws of Newton are not fundamental, but rather emergent. I was talking about the fundamental laws of physics
How about the principle that fundamental equations of motion are differential equations of the order not higher than second?
 
  • #5
Suekdccia said:
Therefore, if the universe had no global symmetries would this mean that all laws of physics (even the most fundamental ones) and fundamental symmetries like the Lorentz or CPT invariances would not be fundamental and unchanging but rather emergent, approximate and with the potential to change in time (at least in a cosmological scale)?
As far as I know Smolins idea is not that the laws change we know change over (from human perspective) cosmological scales as that would likely have left imprints in astronomical observationa we simply havent seen. Smolin entertained in his (cosmological natural selection) the idea that the laws rather changes/mutates at or in an extremely hot early phase after big bang (which we cant observe).

But I think the idea is that yes, there are then no timeless fixed laws. So the whole standard model would be result of evolution.

/Fredrik
 
  • #6
Fra said:
As far as I know Smolins idea is not that the laws change we know change over (from human perspective) cosmological scales as that would likely have left imprints in astronomical observationa we simply havent seen. Smolin entertained in his (cosmological natural selection) the idea that the laws rather changes/mutates at or in an extremely hot early phase after big bang (which we cant observe).

But I think the idea is that yes, there are then no timeless fixed laws. So the whole standard model would be result of evolution.

/Fredrik
But then, If that hot state left the universe without global symmetries, could then the fundamental laws of physics change or evolve (as Smolin says)? Is there any connection to the idea that the fundamental laws could change and the idea that there are no global symmetries? Or are they unrelated?
 
  • #7
Suekdccia said:
But then, If that hot state left the universe without global symmetries, could then the fundamental laws of physics change or evolve (as Smolin says)? Is there any connection to the idea that the fundamental laws could change and the idea that there are no global symmetries? Or are they unrelated?
I would say its related, as symmetries in general are closely related to laws. The difference between global and local symmetries are related to formation/construction of spacetime. In the very early part of big bang this may not make sense.

Its easy to say that something is "emergent", but harder to say how. Emerges from what, and as per what rules?

If the process of emergence follow a dynamical law in a superspace from finetunes initial condition the we would be stuck at the same paradigm (newtonian as smolin calls it- not to be confused with newtonian mechanics) so it would make no sense.

His idea in cns was an unspecified "mutation" of laws that are selected by spawning of new universes that maximise bh production. (Different than my own preferred thinking however)

/Fredrik
 
Back
Top