Tuesday, September 28, 2010

QM => QFT: interpretation?

Roy Simpson writes to me:

Hi Nigel,

I hope that you are progressing with the QFT book: the equations should start to be familiar as you see them in more and more books. One quote that I noticed from this book in Chapter 1 which you have read is very true and very revealing:--

"In fact, there is no wave equation of the type we are used to from non-relativistic quantum mechanics that is truly compatible with both relativity and quantum theory."

This point lies at the centre of trying to conceptually understand QFT, based on a student familiarity with just QM. The fields that QFT introduces are very physical, but it all somewhat leaves poor old Schrödinger and Ψ somewhat out in the cold. The book will have more discussion of this point from a QFT perspective, but where does it all leave QM Interpretations?

I wouldn't blame that book for not resolving this, but this central point seems to leave something to be explained, like a kind of "lessons learnt from QFT" in reinterpreting Ψ.

Also in thinking about Quantum Gravity as "Quantum General Relativity", what hope does such a theory have if we cannot really have a "Quantum Special Relativity"? Hopefully you are interested in these conceptual issues as well.



Hi Roy,

Certainly the ontological/interpretational aspects are the most interesting. My favourite reviewer of all this stuff is arpard fazakas and he is impressed by"A First Course in General Relativity" by Bernard F. Schutz so maybe that's worth looking out for.

Still, one step at a time and who knows, I may get a new contract soon and all this will have to go back on the back-burner ...