Tadpole (physics): Difference between revisions

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In quantum field theory, a tadpole is a one-loop Feynman diagram with one external leg, giving a contribution to a one-point correlation function (i.e., the field's vacuum expectation value). One-loop diagrams with a propagator that connects back to its originating vertex are often also referred as tadpoles. For many theories, these graphs vanish in dimensional regularization.

The physics of tadpoles and the word tadpole was invented by Sidney Coleman. The editor was not satisfied, but he changed his mind once Sidney Coleman proposed spermion instead. Both words are derived from the shape of the Feynman diagram: a circle with a line interval attached to its external side. Tadpole diagrams, in this sense, first appear in the above-mentioned article by Coleman and Glashow, Physical Review B v. 134, p.671 (1964).

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-In [[physics]], a '''tadpole''' is a [[Feynman diagram]] with one external leg, which henceforth encodes a one-point [[correlation function|function]]. The existence of a nonzero tadpole implies that the corresponding field has a nonzero [[VEV]].
+In [[quantum field theory]], a '''tadpole''' is a one-loop [[Feynman diagram]] with one external leg, giving a contribution to a one-point [[correlation function (quantum field theory)|correlation function]] (i.e., the field's [[vacuum expectation value]]). One-loop diagrams with a [[propagator]] that connects back to its originating vertex are often also referred as tadpoles. For many theories, these graphs vanish in [[dimensional regularization]].
 [[Image:tadpole.png]]
-The physics of tadpoles and the word '''tadpole''' was invented by [[Sidney Coleman]]. The editor was not satisfied, but he changed his mind once Sidney Coleman proposed a new word - '''spermion'''. Both words are derived from the shape of the Feynman diagram: a circle with a line interval attached to its external side. Tadpole diagrams, in this sense,
+The physics of tadpoles and the word '''tadpole''' was invented by [[Sidney Coleman]]. The editor was not satisfied, but he changed his mind once Sidney Coleman proposed '''spermion''' instead. Both words are derived from the shape of the Feynman diagram: a circle with a line interval attached to its external side. Tadpole diagrams, in this sense,
-first  appear in the above-mentioned article by  Coleman and Glashow, Physical Review B v. 134, p.671 (1964). Although the term is often used in physics, it has not yet made it into the OED.
+first  appear in the above-mentioned article by  Coleman and Glashow, Physical Review B v. 134, p.671 (1964).
 {{quantum-stub}}