Holographic Models for QCD in the Veneziano Limit

55+32 pages, 16 figuresWe construct a class of bottom-up holographic models with physics comparable to the one expected from QCD in the Veneziano limit of large N_f and N_c with fixed x = N_f/N_c. The models capture the holographic dynamics of the dilaton (dual to the YM coupling) and a tachyon (dual to the chiral condensate), and are parametrized by the real parameter x, which can take values within the range 0 = x_c, and the QCD-like phase with chiral symmetry breaking at x x_c as well as Efimov-like saddle points. By calculating the holographic beta-functions, we demonstrate the "walking" behavior of the coupling in the region near and below x_c