A counterexample to the a-'theorem'

Alfred D. Shapere, Yuji Tachikawa

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


We exhibit a renormalization group flow for a four-dimensional gauge theory along which the conformal central charge a increases. The flow connects the maximally superconformal point of an = 2 gauge theory with gauge group SU(N+1) and Nf = 2N flavors in the ultraviolet, to a strongly-coupled superconformal point of the SU(N) gauge theory with Nf = 2N massless flavors in the infrared. Our example does not contradict the proof of the a-theorem via a-maximization, due to the presence of accidental symmetries in the infrared limit. Nor does it contradict the holographic a-theorem, because these gauge theories do not possess weakly-curved holographic duals.

Original languageEnglish
Article number020
JournalJournal of High Energy Physics
Issue number12
StatePublished - 2008


  • Extended supersymmetry
  • Supersymmetric gauge theory
  • Supersymmetry and duality

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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