Glueballs vs. gluinoballs: Fluctuation spectra in non-AdS/non-CFT

Building on earlier results on holographic bulk dynamics in confining gauge theories, we compute the spin-0 and spin-2 spectra of the Maldacena–Nuñez and Klebanov–Strassler theories, that have non-singular supergravity duals. We construct and apply a numerical recipe for computing mass spectra from certain determinants. In the Klebanov–Strassler case, the spectra of states containing the glueball and gluinoball are universal and quadratic in the supergravity approximation, i.e., their mass-squareds depend on consecutive number as m2∼n2 for large n, with a universal proportionality constant. The hardwall approximation appears to work poorly when compared to the unique spectra we find in the full theory with a smooth cap-off in the infrared.