Recent content by Demystifier

The paper is silly, to put it mildly. The crux of their argument is that the set of axioms is arithmetically expressive and therefore Godel's incompleteness theorems apply. That's silly because there is no reason for a computer program running the simulation to be arithmetically expressive. The...

By the way, this is from the LaTeX book by Lamport.

If doesn't work in relativistic context. For example, if you apply it to Klein-Gordon equation then probability is not conserved.

The main problem is how to define probability density for particle positions. QFT avoids that problem by saying that the theory at the fundamental level is not about particles at all, but about fields. Particles are just excitations of the field, very much like phonons are excitations of a...

I know people who still use Windows XP, without any problems. Hence I do not expect problems with my Windows 10. I will switch to Windows 11 only if I will buy a new desktop/laptop, which I don't plan to do in a near future.

If the fields of the Standard Model are not fundamental, then what is? We don't know. It could be some other fields, or it could be strings, or it could be string fields, or it could be something more abstract as suggested by M-theory, or, if Lorentz invariance is not fundamental, it could even...

I disagree https://www.physicsforums.com/threads/simulating-physics-the-current-status-of-lattice-field-theories.1014629/#post-6626056

There are two kinds on infinities in QFT, UV infinities and IR infinities. UV infinities are due to using a continuum (in both space and time), while IR infinities are due to using infinite extension (in both space and time). And yes, it is known for sure that this is the case.

That's an illegitimate assumption unless ##q(t)## is ##t##-independent. If ##q(t)## depends on ##t## then the charge is not conserved, which is not compatible with Maxwell equations which imply charge conservation.

What do you mean by electron path? It's not even defined, except in the Bohmian interpretation. Since the thought experiment is defined in terms which do not depend on the choice of interpretation, the reversing can only refer to the wave function, not to the electron path. The Bohmian...

Schrodinger didn't know what is the physical meaning of the wave. He only used the nonrelativistic energy formula $$E=\frac{p^2}{2m}+ V(x)$$ Planck's formula $$E=\hbar\omega$$ and de Broglie's formula $$p=\hbar k$$ From this and the ansatz ##\psi=e^{-i\omega t} e^{i kx}## for ##V=0##, the...

If you draw the Feynman diagrams for absorption of one and two photons, you see that they have one and two vertices, respectively, so the latter is suppressed because it is a higher order in the perturbative expansion in ##\alpha##.

Pop science QM is written by actual physicists. They give the best explanation they can under the constraint of not using equations. So when a physicist gives such an explanation of QM in a pop science text, that's because he/she thinks it's essentially correct.

I don't think there is any difference between QM and QFT in that sense. You can certainly think of QFT in terms of ensemble, after all Ballentine in his book has a chapter on quantum optics, which is a QFT. More generally, for any interpretation of QM there is a corresponding generalization to QFT.