What are some coincidences in quantum mechanics that make life possible?

[tzimie]

Could you help to add more items into this incomplete list of life-friendly "coincidences" in QM:

1. Having at least 3 generations is important for life. With 2 or less, CP violation is "absorbed", and without CP violation there is no matter-antimatter disbalance.

2. Neuron is "almost" stable. Having neutron unstable or absolutely stable will be a disaster (for different reasons).

3. There are no stable nuclei with 5 and 8 hadrons, otherwise starts won't be "blocked" on the main sequence for a long time. BTW, why there are no such hadrons? How is it mapped into parameters of the Standard Model?

4...

Thanks

 

[BvU]

How about conservation of uncertainty ?

 

[tzimie]

How about conservation of uncertainty ?

Definitely, sarcasm is not conserved, but grows infinitely like dark energy.
May be my question should belong to Cosmology forum?

 

[Vanadium 50]

This thread is off to a bad start. #1 is not true, and #2 and #3 are not coincidences.

 

[tzimie]

This thread is off to a bad start. #1 is not true, and #2 and #3 are not coincidences.

Could you elaborate (#2 and #3)?

Regarding #1,
https://en.wikipedia.org/wiki/CP_violation

A necessary condition for the appearance of the complex phase is the presence of at least three generations of quarks (if fewer generations are present, the complex phase parameter can be absorbed into redefinitions of the quark fields).

 

[BvU]

And I also have hefty reservations w.r.t. the line above #1. This is a serious physics forum. But humour is of course allowed

 

[tzimie]

And I also have hefty reservations w.r.t. the line above #1. This is a serious physics forum. But humour is of course allowed

Do you suspect that I am talking about the creationism or something like that?
No of course
But I am interested in the fune-tuning in a context of the Multiverse. And of course, this fine-tuning is explained based on Anthropic Principle.
Specifically, I am curious about life-friendly combinations of 19 parameters of the Standard Model, forming one or multiple "clouds" in 19-dimensional space.

 

[Orodruin]

Regarding #1,
https://en.wikipedia.org/wiki/CP_violation

This is only necessary for the CP violation having its origin in mass mixing of Dirac fermions. There are many other possible types of CP violation. For Majorana fermions, two generations are sufficient for CP violation and one of the biggest theoretical problems of today is why strong interactions do not violate CP.

 

[tzimie]

This is only necessary for the CP violation having its origin in mass mixing of Dirac fermions. There are many other possible types of CP violation. For Majorana fermions, two generations are sufficient for CP violation and one of the biggest theoretical problems of today is why strong interactions do not violate CP.

But there are no low energy Majorana fermions (not sure about neutrinos)
So yes, there are many possible types of CP violation, but what kind of CP violation is responsible for actual the matter-antimatter disbalance?

 

[BvU]

Do you suspect that I am talking about the creationism or something like that?
No of course
But I am interested in the fune-tuning in a context of the Multiverse. And of course, this fine-tuning is explained based on Anthropic Principle.
Specifically, I am curious about life-friendly combinations of 19 parameters of the Standard Model, forming one or multiple "clouds" in 19-dimensional space.

You in cahoots with Paul Davies ? I'm more a fan of John Green. I suppose that in PF a physics prof trumps a fiction writer (but the writer's quote gets more likes ).

By the way, don't trust the web site: there are no physics profs that write 'nucleuses'.

 

[Orodruin]

But there are no low energy Majorana fermions (not sure about neutrinos)

Nobody is sure about neutrinos, this is an active field of experimental research.

So yes, there are many possible types of CP violation, but what kind of CP violation is responsible for actual the matter-antimatter disbalance?

We do not know that at this point. The CP violation you are thinking about is far too small to account for the matter-antimatter asymmetry anyway so we already know it is not that one. The most likely scenario is that there are CP violating effects at much higher energies which we have yet to probe. There is no telling whether or not this would require three generations of fermions or not, but there is absolutely nothing which requires it to be a low energy phenomenon.

Edit: Do not get this wrong, the prediction of the third generation of quarks based on the CP violation in the neutral kaon system was a wonderful scientific achievement, well worthy of the Nobel prize it was awarded. However, there is a difference in predicting the third generation based on the observation of CP violation in this particular system and going on from there to claim that it is a requirement for any CP violation.

 

[tzimie]

ok, what's about nuclei with 5 and 8 hadrons?

 

[mfb]

If you look how energy levels in nuclei are filled, it is no surprise that helium-4 has an extremely low energy, which makes nuclei with 5 or 8 nucleons unstable (because they decay to helium+X). To change that, you need a completely different universe.

The production of carbon despite that barrier is more interesting I think, and it lead to the prediction of an excited state of carbon, maybe (!) based on the anthropic principle.