Recent content by Mentz114

I might be completely wrong here - but is a summation implied in $$\epsilon^{ab}\overline Q^i_{La} \phi^{\dagger}_b$$ The indices a and b are dummies and imply a sum over values of a and b which occur in upper and lower positions. For instance an inner product is written ##\mathbf{u} \cdot...

In the text "Quantum Field Theory" by Itzykson & Zuber (1985) the word 'phase' has 3 entries in the index referring to 'phase space' and 'phase shifts'.

The word 'phase' in statistical physics can mean a phase of matter such as solid, liquid, vapour or plasma. Naturally in QFT it means something different. Different phases of matter can co-exist at their boundary and this is sometimes called a superposition. See for instance Rao, Statistical...

With respect, surely using analogies like of wavefronts and updates is old-fashioned, as is looking for mechanisms. The problem is handled in QFT by creating whatever is required in the inputs of the BS and evolving this state. The calculation agrees with experiment but it tells us nothing...

Read the paper I cited. QFT gives the correct prediction for 'matter-waves'.

Well, nearly no-one. https://arxiv.org/abs/1103.0100

Even if the only particles that exist are the ones in our calculation then predicting results correctly means the theory is working. Assuming that this or that element in the calculation actually exists is speculative for anything that is below a certain size. Which means that dialectic on this...

I do not agree that the MP is a mystery. The fact that QT only predicts probabilities means that QT ( ie unitary evolution) cannot predict the outcome of an experiment any more than a thermometer can meaure length. This only a problem if it is assumed ( incorrectly) that probability has any...

Agreed. I think the claim that 'QT has contradictions' is unsupported and there is no list.

That's interesting. Can you list them ?

Sorry if I mislead you. Just to make my point about how tricky 'infinite conductivity' is, look at this (great) paper https://academic.oup.com/ptps/article-abstract/doi/10.1143/PTPS.86.43/1885987 My mistake is not remembering that it is the time derivative of the Nambu-Goldstone field that must...

Probably beacuse the electrical formula ##V=IR## suggests this with zero resistance.

If you are learning QT then starting with super-conductivity is bold ( and probably unwise). It is an interesting feature of this phenomenon that the equations predict that with a constant voltage applied across the superconductor a constant current flows. We cannot say why - it just happens...

I've been solving these two ODEs ##\frac{d}{d\,r}\,A=F(A,r) + \epsilon f(r)## and ##\frac{d}{d\,r}\,A=F(A,r)##. If the solutions are respectively ##A_1(r,\epsilon)## and ##A_2(r)## then will ##A_1(r,0) = A_2(r)## ? I realize the answer could depend on the actual functions but with the ones...

I must say I do not agree. If QFT predicts that a 'collision' between succesive molecules and the slits produces an interference pattern - what is incoherent about that ?