  We study quantum gravitational effects on black hole radiation, using loop
quantum gravity. Bekenstein and Mukhanov have recently considered the
modifications caused by quantum gravity on Hawking's thermal black-hole
radiation. Using a simple ansatz for the eigenstates the area, they have
obtained the intriguing result that the quantum properties of geometry affect
the radiation considerably, yielding a definitely non-thermal spectrum. Here,
we replace the simple ansatz employed by Bekenstein and Mukhanov with the
actual eigenstates of the area, computed using the loop representation of
quantum gravity. We derive the emission spectra, using a classic result in
number theory by Hardy and Ramanujan. Disappointingly, we do not recover the
Bekenstein-Mukhanov spectrum, but --effectively-- a Hawking's thermal spectrum.
The Bekenstein-Mukhanov result is therefore likely to be an artefact of the
naive ansatz, rather than a robust result. The result is an example of concrete
(although somewhat disappointing) application of nonperturbative quantum
gravity.
