  We estimate the thermal width of a heavy quark anti-quark pair inside a
strongly coupled plasma using a holographic AdS/QCD model. The imaginary part
of the quark potential that produces the thermal width appears in the gravity
dual from quantum fluctuations of the string world sheet in the vicinity of the
horizon. The results, obtained using a soft wall background that involves an
infrared mass scale, are consistent with previous analisys where the mass scale
was introduced by averaging over quark anti-quark states.
