Abstract:
We review and extend our recent work on the planar (large N) equivalence between gauge theories with varying degree of supersymmetry. The main emphasis is made on the planar equivalence between N=1 gluodynamics (super-Yang-Mills theory) and a non-supersymmetric orientifold field theory. We outline an orientifold large N expansion, analyze its possible phenomenological consequences in one-flavor massless QCD, and make a first attempt at extending the correspondence to three massless flavors. An analytic calculation of the quark condensate in one-flavor QCD starting from the gluino condensate in N=1 gluodynamics is thoroughly discussed. We also comment on a planar equivalence involving N=2 supersymmetry, on chiral rings in non-supersymmetric theories, and on the origin of planar equivalence from an underlying, non-tachyonic type-0 string theory. Finally, possible further directions of investigation, such as the gauge/gravity correspondence in large-N orientifold field theory, are briefly discussed.
Note:
  • To be published in the Ian Kogan memorial collection 'From Fields to Strings: Circumnavigating Theoretical Physics', World Scientific, 2004
  • 106 pages, LaTex. 15 figures. v2:minor changes, refs. added. To be published in the Ian Kogan Memorial Collection "From Fields to Strings: Circumnavigating Theoretical Physics," World Scientific, 2004
  • gauge field theory: SU(N)
  • supersymmetry: superfield
  • supersymmetry: superspace
  • expansion 1/N
  • vacuum state
  • orbifold
  • orientifold
  • Feynman graph: planar
  • fermion: flavor
  • energy