Is quantum field theory a genuine quantum theory?

  • #1
Science Advisor
Insights Author
Gold Member
In my recent paper
"Is quantum field theory a genuine quantum theory? Foundational insights on particles and strings"
I argue the following:

Practically measurable quantities resulting from quantum field theory are not described by hermitian operators, contradicting one of the cornerstone axioms of orthodox quantum theory. This could be a sign that some of the axioms of orthodox quantum theory should be reformulated. A non-orthodox reformulation of quantum theory based on integral curves of particle currents is advocated and possible measurable manifestations are discussed. The consistency with particle creation and destruction requires particles to be extended objects, which can be viewed as a new derivation of string theory. Within this reformulation, an indirect low-energy test of string theory is also possible.

Comments are wellcome! :smile:

Answers and Replies

  • #2
your argument seems to be the abstract of the paper.but the point is that the foundations of QFT are still in the process of being established, i belive.Axiomatic field theory, in the same sense quant mech is, doesnt exist as yet.when you start QFT, you dont begin with a series of axioms, like u do in q mech. that makes a whole lot of difference. reformulating QM without first axiomatically formulating QFT doesnt seem an attractive idea to me.
  • #3
Science Advisor
Insights Author
Gold Member
It seems that you have not been reading the paper itself, only the abstract.
One of the points is that the practically measurable objects are particles, rather than fields. This is why I chose to reformulate particle QM, where particles are fundamental (not merely emergent as in QFT) objects.
  • #4
The consistency with particle creation and destruction requires particles to be extended objects
Loosely speaking I think I follow your line of reasoning, and while I don't necessarily agree upon the objectification, I agree that a desirable consistency in the line of reasoning suggest that the axioms of QM doesn't make sense in the general case.

I think part of the problem traces back to the probabilistic framework. I think it doesn't take too much thinking to realize that the idea of having a complete map of all present and future possibilities are simply idealized to an extent where it makes no sense. To associate a complete Hilbert space to a complete state space of reality is an major stretch to me.

As it seems, a simple example is where previously unknown structure or interactions yield states that is outside of the original set of possibilities.

But I think this is a common thing in any evolution, and certainly not something weird. But the axioms completely fail to adapt to this. The normal resolution is then to assume a bigger space and some second quantization, of which the original one is a special case. But this is made with a broken line of reasoning in a, ad hoc manner, that in my book doesn't hold acceptance.

I think there should be a natural way for events to split, and associate in a dynamical manner. And if there is to be some scaling symmetry in the reasoning, expected by a general case, the splitting and associationgs must be able to take place iteratively. I'm currently trying to implement this, but haven't succeded yet. When I've been thinking about these things my own conclusion is that the observers self interaction (processing, or thinking) is a factor here, as it remodels the estimated event space. And this seems messy because the observers self-change somehow must qualify as changes, beeinga factor in time parameter.

At first it seems impossible to solve a part without solving the hole, but I think the solution is to see it as a learning evolution, and I am working on identifying the induction step.

In this sense, it could in principle be that a particle will on it's own, evolve into a string, or a membrane... but it will not do so on a general basis (causing a massive increase in degrees of freedom), I think it will do so on an as needed basis, in a dynamical way. I never wished to ban strings, the point is that I fail to see how it qualifies as a sensible starting point.

I'm not deeply into string theory, but my hunch is that perhaps there is a link somewhere... and if so it seems plausible that the landscape problem is present. If the strings are not blown up on a general basic, but rather on an as needed basis (yes this term is to be elaborated) the model should make the proper selection as it evolves. It should not need to involved ad hoc elaborations? I for one, will still ask "why strings".

Disclamer: this is a intuitive comment only. I'm working on things and won't argue formally at this point, since I've got alot of work undone. I'm just throwing out reflections as food for thought.


Related Threads on Is quantum field theory a genuine quantum theory?