Does QCD make sense without a cutoff?

[PeterDonis]

It's not a matter of dispute, it's just an unanswered question. As I said, I don't care, where we discuss this.

What is there to discuss if we can't do the experiment?

 

[vanhees71]

Well, we are doing experiments all the time to learn about all aspects of strongly interacting matter in heavy-ion collisions (LHC with the highest available energies, RHIC, GSI) and construct new big experiments (FAIR, NICA, the EIC at BNL,...) or investigate them by astronomical observations of neutron stars and neutron-star mergers in all ranges of the em. spectrum and for some years with gravitational waves.

We learn more and more about all aspects of the strong interaction and strongly interacting matter (and thus also QCD).

 

[A. Neumaier]

And as far as I can tell, the answer is that it's a matter of opinion.

The subforum is called 'Quantum Interpretations and Foundations' and not 'Opinions on quantum physics'. The main forum expresses lots of opinions about quantum physics (perhaps more than 50%). Statements by experts are still opinions, and often challenged in the main forum.

Based on its current contents, excepting the present thread, the subforum is about the interpretation of the foundational aspects of quantum mechanics, not about comparing different approaches to get numbers from theory (which is fully shut-up-and-calculate).

 

[vanhees71]

It's also not an issue of opinions but an open question about solid research in physics and mathematics in contradistinction to philosophical issues of belief in the one or the other interpretation of QM!

 

[PeterDonis]

Based on its current contents, excepting the present thread, the subforum is about the interpretation of the foundational aspects of quantum mechanics

Yes, that's what it was originally split off for.

However, that split also clarified what the regular QM forum is for: it's for discussions that fall within the 7 basic rules of QM, the Insights article for which you authored.

The present thread, at least based on its title and stated topic in the OP, does not fall within those guidelines. See below.

comparing different approaches to get numbers from theory (which is fully shut-up-and-calculate).

The title and OP of the present thread did not ask about comparing different approaches to get numbers from theory. It asked about whether one approach (the one without a cutoff) "makes sense". That question is not a "shut up and calculate" question that falls within the 7 basic rules referred to above.

It seems like your position is that the answer to the title question of this thread is a simple "yes". If @Demystifier, who started this thread, agrees with that answer, we can simply close this thread with that answer, and then if someone wants to start a new thread in the regular QM forum that does fall within the regular QM forum guidelines, particular posts in this thread could be moved to that one upon request. I am perfectly willing to help facilitate that.

If, OTOH, @Demystifier does not agree with that "yes" answer to the title question, any argument about it is not going to fall within the guidelines of the regular QM forum. It doesn't seem like this thead has contained much of an argument about it, which leads me to believe that the simple "yes" answer is in fact correct. But that just puts us back to the situation I described in the last paragraph: we can simply close this thead and someone can start a new one in the regular QM forum whose stated topic falls within the guidelines for that forum.

 

[A. Neumaier]

However, that split also clarified what the regular QM forum is for: it's for discussions that fall within the 7 basic rules of QM, the Insights article which you authored.

The present thread, at least based on its title and stated topic in the OP, does not fall within those guidelines.

Not only @Demystifier, @vanhees71, and me (the main contributors to this thread), but also several former mentors (@George Jones, @Vanadium 50) are sceptical about your decision; perhaps confer with them and reconsider your point of view.

I don't see the slightest hint that would suggest that the title or any post in this thread is outside the 7 basic rules of QM. To ask whether some technical modeling assumption in QFT makes sense does not call these guidelines into question.

It is like asking in the relativity section whether assuming slight violation of Lorentz invariance or a discrete spacetime make sense. While outside the mainstream, these are legitimate questions discussed in the published refereed literature. Of course it is only a matter of opinion whether one answers yes or no, but the justification of the answer and discussion of work done on it involves nontrivial issues of interest.

The same holds for the question about how to get a relativistic QFT from an underlying nonrelativistic QFT by a scaling limit. What is discussed in the present thread is closely related to this.

 

[atyy]

Not only @Demystifier, @vanhees71, and me (the contributors to this thread), but also several former mentors (@George Jones, @Vanadium 50) are sceptical about your decision; perhaps confer with them and reconsider your point of view.

The reason I believe it should remain in Interpretations is that otherwise @vanhees71's priceless post #10 would be deleted

 

[PeterDonis]

Thread closed for moderation.

 

[PeterDonis]

The moderators have reviewed this thread and determined that it should stay in the interpretations and foundations forum. Note that "foundations" is part of the forum's title, and the discussion in this thread, in the opinion of the moderators, qualifies as a "foundations" discussion.

For now the thread will remain closed; if any participants have further posts they would like to make, feel free to PM me to request that it be reopened.