Talk:Dyson series

On convergence

Is the first paragraph meant to say that the series *converge* rather than diverges? Wrath0fb0b 02:56, 28 February 2006 (UTC)

See this excellent answer on Stack Exchange: https://physics.stackexchange.com/questions/357311/question-about-convergence-of-dyson-series-why-dyson-series-is-in-general-diver BruceThomson (talk) 01:13, 2 June 2022 (UTC)

If that's the Neumann series then it's Carl Neumann, not Johnny.

Charles Matthews 08:23, 19 February 2006 (UTC)

Corrected. 192.165.166.4 19:54, 21 February 2006 (UTC)

I did not write the article but the series diverges, it does #not# converge.

That can't be uniformly true for an arbitrary perturbation. It's certainly true for relativistic fields when the perturbation is the introduction of interactions, but it's certainly not true under all circumstances. Mpalenik (talk) 15:28, 20 May 2016 (UTC)

Is this a general property, or is it specific to some potential V ? I would say convergence depends on the latter, unless I miss something obvious... ? Tlesinski (talk) 19:39, 11 June 2009 (UTC)

You also use the Dyson series in nonlinear physics (solution of Kramers-Moyal-Expansion). Perhaps anybody can add this to this category

The exponentiation of the "free" part is missing in the Tomonaga-Schwinger relation written here, both for the potential part and for the vector. 139.124.7.126 09:03, 18 July 2007 (UTC)

Shouldn't the first exponent in the last formula (overlap of wavefunctions) be +i H_0 ... instead of -i H_0 etc.? 128.130.48.239 (talk) 14:05, 27 May 2009 (UTC)

merge

Anyone else think this article should be merged into a section of ordered exponential (or even with path-ordering)? For example, then a derivation could be given just once.. Cesiumfrog (talk) 00:47, 14 March 2010 (UTC)

If the present article should go, I do not know, but to have this Dyson stuff as an application in OE is a good idea. 2A01:CB0C:CD:D800:60FE:A4E2:BB36:340C (talk) 11:50, 3 April 2021 (UTC)

please make the interaction image more visible

simply write $U_{I}$ instead of U. This would be clearer!--92.202.25.74 (talk) 19:23, 4 December 2013 (UTC)

That really does not make things any more or less clear. 2A01:CB0C:CD:D800:60FE:A4E2:BB36:340C (talk) 11:47, 3 April 2021 (UTC)

Meaning and significance

Could someone write a brief description of what the Dyson Series is "about" in layman's terms, and its significance. Cellmaker (talk) 11:28, 19 April 2018 (UTC)

and hence the Tomonaga–Schwinger equation,

The hence is obscure here. The text introduces the operator U, lists its group properties, and then says hence as if the T-S follows from just that. 2A01:CB0C:CD:D800:60FE:A4E2:BB36:340C (talk) 11:47, 3 April 2021 (UTC)