Small instantons in string theory

Edward Witten

Research output: Contribution to journalArticlepeer-review

558 Scopus citations

Abstract

A long-standing puzzle about the heterotic string has been what happens when an instanton shrinks to zero size. It is argued here that the answer at the quantum level is that an extra SU (2) gauge symmetry appears that is supported in the core of the instanton. Thus in particular the quantum heterotic string has vacua with higher rank than is possible in conformal field theory. When k instantons collapse at the same point, the enhanced gauge symmetry is Sp (k). These results, which can be tested by comparison to Dirichlet five-branes of Type I superstrings and to the ADHM construction of instantons, give the first example for the heterotic string of a non-perturbative phenomenon that cannot be turned off by making the coupling smaller. They have applications to several interesting puzzles about string duality.

Original languageEnglish (US)
Pages (from-to)541-559
Number of pages19
JournalNuclear Physics B
Volume460
Issue number3
DOIs
StatePublished - Feb 12 1996
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics

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