Non-Perturbative Planar Equivalence and the Absence of Closed String Tachyons
نویسنده
چکیده
We consider ’orbifold’ and ’orientifold’ field theories from the dual closed string theory side. We argue that a necessary condition for planar equivalence to hold is the absence of a closed string tachyonic mode in the dual non-supersymmetric string. We analyze several gauge theories on R × S. In the specific case of U(N) theories with symmetric/anti-symmetric fermions (’orientifold field theories’) the relevant closed string theory is tachyon-free at large compactification radius (due to winding modes), but it develops a tachyonic mode below a critical radius. Our finding is with agreement with field theory expectations of a phase transition from a C-parity violating phase to a C-parity preserving phase as the compactification radius increases. In the case of U(N) × U(N) theories with bi-fundamental matter (’orbifold field theories’) a tachyon is always present in the string spectrum, at any compactification radius. We conclude that on R planar equivalence holds for ’orientfiold field theories’, but fails for ’orbifold field theories’ daughters of N = 4 SYM and suggest the same for daughters of N = 1 SYM. We also discuss examples of SO/Sp gauge theories with symmetric/anti-symmetric fermions. In this case planar equivalence holds at any compactification radius in agreement with the absence of tachyons in the string dual.
منابع مشابه
Closed-string Tachyon Condensation and On-shell Effective Action of Open-string Tachyons
We study how the effect of closed-string tachyon condensation can enter into the on-shell effective action of open-string tachyons, for bosonic case. We also consider the open-string one-loop quantum corrections to the action. We use sigma-model approach with boundary terms, and we utilize some results of boundary string field theory (BSFT) to define the on-shell effective action. We regard D-i...
متن کاملUnstable magnetic fluxes in heterotic string theory
We study exact string backgrounds representing a constant magnetic field background in heterotic string theory. These backgrounds are obtained by Kaluza-Klein reduction of a special class of plane wave solutions. For small values of the magnetic field they possess localized closed string tachyons analogous to the Nielsen-Olesen instability of a constant magnetic field in SO(3) Yang-Mills theory...
متن کاملPerturbative Gauge Theory and Closed String Tachyons
We find an interesting connection between perturbative large N gauge theory and closed superstrings. The gauge theory in question is found on N D3-branes placed at the tip of the cone R/Γ. In our previous work we showed that, when the orbifold group Γ breaks all supersymmetry, then typically the gauge theory is not conformal because of doubletrace couplings whose one-loop beta functions do not ...
متن کاملDon’t Panic! Closed String Tachyons in ALE Spacetimes
We consider closed string tachyons localized at the fixed points of noncompact non-supersymmetric orbifolds. We argue that tachyon condensation drives these orbifolds to flat space or supersymmetric ALE spaces. The decay proceeds via an expanding shell of dilaton gradients and curvature which interpolates between two regions of distinct angular geometry. The string coupling remains weak through...
متن کاملHybrid Inflation in Intersecting Brane Worlds
Non-supersymmetric brane world scenarios in string theory display perturbative instabilities that usually involve run-away potentials for scalar moduli fields. We investigate in the framework of intersecting brane worlds whether the leading order scalar potential for the closed string moduli allows to satisfy the slow-rolling conditions required for applications in inflationary cosmology. Adopt...
متن کامل