I appreciate your feedback - can you comment on how the QFT Lagrangian is structured to implement the requirement you outline to ensure that 'no "unphysical degrees of freedom" mix into the dynamics and thus contribute to the S-matrix' ? As the Lagrangian solves for the final field structure...
In an earlier question I asked if the EM field was truly a separate field from the matter field in QFT, as it's field structure is naturally complementary to phase changes in the matter field in just the right way to restore gauge invariance (poorly formed question, but hopefully you get the...
It seems that QED treats the matter and EM fields as independent yet coupled fields. On the other hand the EM field equations emerge immediately under local change of the phase of the matter field, exactly as required to reestablish local (gauge) invariance. From that perspective it almost seems...
I'll like to state a core question I have regarding QFT field coupling in more detail. There have been two effects of EM field coupling to the electron mater field described: (1) acceleration of the electron (matter field) in response to an external EM field and (2) an interaction of the...
I am a lay person with an interest in QFT and trying to learn (although I do have bachelors degrees in mathematics and physics), so would appreciate any coaching toward terminology that may be more standard within the field of study. I was trying to communicate that the two fundamental QFT...
Thank you for the very clear explanation, that is helpful. The coupling explanation raises a point from an earlier post, namely that the electron matter field raises the potential energy level in the local EM field (the 'attached' field) but can it be said that the EM field does the same in...
I follow the general outline of the discussion and appreciate the exposure to the Wilson references which are quite interesting. I didn't quite follow the reference 'the e/m field field is the result of the self-interaction through the mediation of the e/m field.' which achieves an admirable...
Thanks for the clarification - is this the source of the re-normalization issue which required the empirical adjustment to cancel in QFT calculations or is that a separate issue?
My understanding of the QFT model of a free electron is that there is a localized higher energy level in the electron matter field which couples to the EM field in two ways: (1) the coupling allows the electron matter field to 'feel' a force from an outside EM field and accelerate in response...
That's very helpful, thanks. Just to clarify, in the use of the term 'attached EM field of an electron' does this refer to a elevation of the energy level of the local EM field neighboring the electron, ie. is there truly just one pervasive EM field and not separate 'attached' fields in...
This is an elementary question on visualizing the interaction of an electron with the surrounding EM field in QFT. I believe in QFT the electron is viewed as an excitation of the Electron matter field with an associated coupling constant between the electron field and EM field (say q) - q...
Many thanks, this feedback has been very helpful! With respect to the stress energy tensor, it does make sense that the mixed signature implications have an impact on this tensor (and thus generated geometry/gravity) at high velocity/energies and hence things are not 'truly separable' - in...
Perhaps a step back to clarify the context of the question might be beneficial. The question came up in thinking of how GR reduces to SR
(in the simplest case of zero matter). As a thought experiment (not a viable theory) , if one could create an accurate model of gravity as spacetime
curvature...
The question came up in thinking of how GR reduces to SR (in the simplest case of zero matter). As a thought experiment (not a viable theory) , if one could create an accurate model of gravity as spacetime curvature using only a positive definite metric it would clearly show that In the SR...
So by posulate, do you mean that it is a separate (independant) assumption which is not logically (mathematically) required to formulate a curved spacetime description of gravity?
In considering special relativity as a limiting case of the general theory (without matter or curvature) the question arose as to whether the pseudo-riemann nature of the SR metric is actually an independant (essentially experimentally determined) assumption/property or derivable from the...