nLab solitonic brane




In string theory the term solitonic brane refers to brane-like solutions of equations of motion in (super-)gravity whose presence is imprinted in topologically stable configurations of background fields of the ambient spacetime, notably in the gravitational field and the higher gauge field-flux for which the brane is a source. This is in contrast to fundamental branes or probe branes described by sigma models with target space the given spacetime, whose trajectories are effected by such background fields but which do not themselves backreact on them.

More specifically, when the term “solitonic brane” was introduced in Duff, Khuri & Lu (1992), (1994) and Duff & Lu (1994) it referred concretely to “topologically stable” but non-singular sugra-solutions, hence those for which the background field strength/curvature is finite on all of spacetime as one may expect to be the case for solitons — this in contrast to singular- or black branes whose would-be locus in spacetime is a “singularity” where these fields diverge, in higher dimensional generalization of the situation for black holes.

However, while the term “solitonic brane” has become common place, authors often use it with somewhat different meaning. (For better or worse, already the reference term soliton in field theory is used in a variety of neighbouring but different meanings.)

Another convention [Stelle (1998), Bergshoeff & Riccioni (2012)] is to say “solitonic” for the singular magnetically charged brane solutions (eg. the black NS5-brane) which are the electromagnetic duals to the “elementary” (namely just as singular but) electrically charged brane solutions (eg. the black string). In this convention the adjective “solitonic” is not distinguishing between singular/non-singular fields, but identifies the secondary magnetic sources for given primary degrees of freedom. For instance in this terminology and regarding the electron as the fundamental particle that it is, the magnetic monopole would be its “solitonic” dual version.

But nowadays many authors (eg. Smith (2002), p. 5) use “solitonic brane” to subsume all singular and non-singular brane-like supergravity solutions, hence use the term generally as the antonym to fundamental/elementary branes (a terminology that is not used fully consistently across authors, either), ie. as antonym to branes described by sigma-models.


Last revised on July 1, 2023 at 19:41:57. See the history of this page for a list of all contributions to it.