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• CommentRowNumber1.
• CommentAuthorUrs
• CommentTimeAug 27th 2014
• (edited Aug 27th 2014)

in the process of writing zeta function regularization etc. I also created a stub for Feynman propagator/Dirac propagator .This now has some key pointers, but the entry remains very stubby.

• CommentRowNumber2.
• CommentAuthorUrs
• CommentTimeAug 4th 2017
• (edited Aug 4th 2017)

Am about to write up the rigorous definition of all things propagators (Feynman propagator, advanced/retarded propagator, etc.) for scalar fields on globally hyperbolic spacetimes. There is a beautiful graphical calculus in terms of wave front sets for this, which I finally grasped from Radzikowski 96 (a remarkably pivotal reference for rigorous quantum field theory on curved spacetimes). The calculus without words is now tabulated here. Have to call it quits for tonight. More later.

• CommentRowNumber3.
• CommentAuthorUrs
• CommentTimeAug 5th 2017
• (edited Aug 5th 2017)

Okay, I have further fine tuned and then split off the table as a table for inclusion in related entries

Igor Khavkine kindly provided a correct picture of the wave front set for the Hadamard propagator, and we expanded a bit more the text at Klein-Gordon equation – Fundamental solutions.

• CommentRowNumber4.
• CommentAuthorUrs
• CommentTimeSep 6th 2017
• (edited Sep 6th 2017)

I have given Feynman propagator a decent Idea-section (or so I hope). Then I added statement and proof that the general formula expressing the Feynman propagator $\omega_F$ as the sum of the vacuum 2-point function $\omega$ with the advanced propagator $\Delta_A$

$\omega_F = \omega + i \Delta_A$

yields the contour integral presentation that one finds in the standard textbooks (this prop.)

• CommentRowNumber5.
• CommentAuthorAnisomorphism
• CommentTimeNov 15th 2023

added/fixed the reference to Gel’fand and Shilov’s generalized functions text as per the causal propagator page and Israel Gel’fand’s page

• CommentRowNumber6.
• CommentAuthorUrs
• CommentTimeNov 15th 2023

Thanks for this and the other edits.

I have further expanded the bibitem (here), such as adding the ISBN with a link and also a link to Georgiy Shilov.

• CommentRowNumber7.
• CommentAuthorUrs
• CommentTimeNov 15th 2023

Thanks for this and the other edits.

I have further expanded the bibitem (here), such as adding the ISBN with a link and also a link to Georgiy Shilov.

• CommentRowNumber8.
• CommentAuthorUrs
• CommentTimeNov 15th 2023

also made the fix (2.11 $\mapsto$ 2.10) in the text (trusting you here, I haven’t double checked myself again)

• CommentRowNumber9.
• CommentAuthorAnisomorphism
• CommentTimeNov 15th 2023
Thank you, I hadn't gotten around to correcting it all in the article yet. I was reading through the whole page on propagators so I made sure that this is the correct section of Generalized Functions, I have the volume on me. I will keep your reference formatting style in mind for when I make future changes.