Confinement Potential in a Soft-Wall Holographic Model with a Hydrogen-like Spectrum

Abstract: It is well known that the Soft-Wall holographic model for QCD successfully reproduces not only the linear Regge spectrum, but also, via the holographic Wilson confinement criterion, the ''linear plus Coulomb'' confinement potential similar to the Cornell potential. This property could be interpreted as a holographic counterpart of the hadron string picture, where the linearly rising potential and Regge-like spectrum are directly related. However, such a relation does not take place in the bottom-up holographic approach. Namely, the Cornell-like potentials arise in a broad class of bottom-up holographic models, the standard Soft-Wall model is merely a particular representative of this class. We consider a calculation of confinement potential within a different representative of this class - a Soft-Wall model with linear dilaton background in the metric. This model leads to a Hydrogen like spectrum. The calculation of renormalized potential at short distances turns out to be complicated by a new subtlety that was skipped in general discussions of the issue existing in the literature. But the confinement potential of the model is shown to be not very different from the potential obtained in the standard Soft-Wall model with quadratic background.