Radiation Gauge in AdS/QCD: Inadmissibility and implications on spectral functions in the deconfined phase

We point out a subtlety in choosing the radiation gauge (Az=0Az=0 combined with the Lorenz gauge) for gauge fields in AdS/QCD for black hole backgrounds. We then demonstrate the effect of this on the momentum-dependence of the spectral functions of the J/ψJ/ψ vector meson, showing a spreading with momentum and a breaking of isotropy, in contrast to previous results in the literature. We also discuss the dependence on a background magnetic field, following our earlier proposed model.