Talk:Effective action

Untitled

The image supplied before was misleading, as the diagram(s) shown do not arise in the expansions for any of the functionals discussed in this article. I have replaced it, trying to preserve the original intention and hopefully doing a better job at illustrating the relevant diagrams. Y!qtr9f 15:53, 29 April 2006 (UTC)

no group action

What about including a reference to the mathematical notion of action of a group? Some authors also use the term "effective action" in that context.

WikiProject class rating

This article was automatically assessed because at least one WikiProject had rated the article as stub, and the rating on other projects was brought up to Stub class. BetacommandBot 09:49, 10 November 2007 (UTC)

Footnotes vs Parenthesis

Is it possible to change the parenthetical comments in the following sentence to footnotes for the sake of clarity?

"Just as Z is interpreted as the generating functional (aka characteristic function(al)/moment-generating function(al) of the probability distribution function(al) e-S[φ]/Z) of the time ordered VEVs/Schwinger function (aka moments) (see path integral formulation), E (aka the second characteristic function(al)/cumulant-generating function(al)) is the generator of "connected" time ordered VEVs/connected Schwinger functions (i.e. the cumulants) where connected here is interpreted in the sense of the cluster decomposition theorem which means that these functions approach zero at large spacelike separations, or in approximations using feynman diagrams, connected components of the graph." 84.142.53.39 (talk) 00:38, 4 July 2010 (UTC)

One loop approximation

Clearly this article needs all of its sections fleshed out, however I feel that the "One loop approximation" section is severely lacking. Some explanation of what the equation means is really required, as well as explanation of the notation used. A reader without formal knowledge of the calculation may find S⁽²⁾ unclear and may need it to be explained. — Preceding unsigned comment added by PhysicsSean (talk • contribs) 10:58, 15 February 2018 (UTC)

Complete rewrite

Since this article has been around for years largely unaltered, I went on and rewrote it entirely. I used the previous version for key structural ideas and trying to keep the information around, albeit in a new form. I did however get rid of some things: I did got rid of the unreadable list of alternative names for the generation functional, as well as dropping de Witt notation since it is entirely redundant to have all equations around twice.

I did however add new information too: elaborated on the three types of generation functionals to draw attention to their similarities and differences, showed how these can be used to find the full propagator, fixed up the one-loop approximation (finding a reference for it too), created some figures, added in-text references, and introduced some additional information relating to the symmetries of the effective action and the convexity of the effective potential. (Lonewolf709 (talk) 23:31, 6 September 2021 (UTC))