Gravity duals of fractional branes and logarithmic RG flow Original Research Article

We study fractional branes in N=2 orbifold and N=1 conifold theories. Placing a large number N of regular D3-branes at the singularity produces the dual AdS5×X5 geometry, and we describe the fractional branes as small perturbations to this background. For the orbifolds, X5=S5/Γ and fractional D3-branes excite complex scalars from the twisted sector which are localized on the fixed circle of X5. The resulting solutions are given by holomorphic functions and the field-theoretic beta-function is simply reproduced. For N regular and M fractional D3-branes at the conifold singularity we find a non-conformal N=1 supersymmetric SU(N+M)×SU(N) gauge theory. The dual Type IB background is AdS5×T1,1 with NS–NS and R–R 2-form fields turned on. This dual description reproduces the logarithmic flow of couplings found in the field theory.