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    I QFT and Gauge Invariance

    That is a perfect explanation, many thanks!
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    I QFT and Gauge Invariance

    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...
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    I QFT and Gauge Invariance

    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...
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    I Relationship between EM and matter fields in QED

    Many thanks to everyone for some very insightful replies on the topic!
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    I Relationship between EM and matter fields in QED

    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...
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    I Visualizing the Attached EM Field for Free Electron in QFT

    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...
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    I Visualizing the Attached EM Field for Free Electron in QFT

    Perhaps I should say something like 'an excitation of the electron matter field couples to raise a local excitation of the EM field'
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    I Visualizing the Attached EM Field for Free Electron in QFT

    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...
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    I Visualizing the Attached EM Field for Free Electron in 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...
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    I Visualizing the Attached EM Field for Free Electron in QFT

    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...
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    I Visualizing the Attached EM Field for Free Electron in QFT

    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?
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    I Visualizing the Attached EM Field for Free Electron in QFT

    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...
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    I QFT Interpretation of Electron and Attached EM Field

    Thanks to all, this has been very helpful!
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    I QFT Interpretation of Electron and Attached EM Field

    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...
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    I What is an electron in QED?

    FYI, Feynman came over to the field viewpoint later in life - see reference in Julian Schwinger's Climbing the Mountain.
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    I QFT Interpretation of Electron and Attached EM Field

    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...
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    Is a Pseudo-Riemann Metric Intrinsic to General Relativity?

    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...
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    Is a Pseudo-Riemann Metric Intrinsic to General Relativity?

    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...
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    Is a Pseudo-Riemann Metric Intrinsic to General Relativity?

    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...
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    Is a Pseudo-Riemann Metric Intrinsic to General Relativity?

    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?
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    Is a Pseudo-Riemann Metric Intrinsic to General Relativity?

    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...
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