Weinberg, Vol. 1: Path Integrals Query

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SUMMARY

The discussion centers on the path integral quantization of Quantum Electrodynamics (QED) as presented in Weinberg's Volume 1. The user expresses confusion regarding the integration of matter field momenta for spinor fields, specifically referencing equations (9.6.5) and (9.5.56). A clarification from Steven Weinberg indicates that the adjoint spinor is indeed integrated out, although the user questions the convention of treating \(\psi^\dagger\) as an independent field. This highlights a critical aspect of path integral formulation in Quantum Field Theory (QFT).

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  • Understanding of Quantum Field Theory (QFT)
  • Familiarity with path integral formulation
  • Knowledge of spinor fields and their properties
  • Proficiency in mathematical notation used in QFT, particularly integration conventions
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  • Study the path integral formulation of QED in detail, focusing on Weinberg's Volume 1
  • Review the integration of spinor fields and the treatment of adjoint spinors
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Students and researchers in theoretical physics, particularly those focusing on Quantum Field Theory and the path integral approach to QED. This discussion is beneficial for anyone seeking to deepen their understanding of Weinberg's methodology and the nuances of spinor field integration.

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I am trying to study QFT from Weinberg's Vol. 1.

I am at the moment stuck at the path integral quantization of QED (Weinberg's treatment).

I am not sure how he integrates out the matter field momenta (for the spinor field) in eq. (9.6.5). I thought for spinor fields you don't do that.

I thought that there should be integration with respect to p_m as given in eq. (9.5.56).

Any help will be much appreciated.
 
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I think he just didn't bother to write d\psi^\dagger. This is essentially a matter of convention as to whether we think of \psi^\dagger as an independent field or not.
 
QFT: Path Integrals, Weinberg Vol. 1

I had e-mailed SW about this, he told me that it was integrated out.

My understanding is fairly minimal, but from (9.5.1), (9.5.49) and (9.5.52), I didn't think
the adjoint spinor could be integrated out. If you could give me a reference, and/or a hint that would be great. I thought one needed equal amounts of \psi and \psi adjoint terms.

Thanks for your message.
 

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