Microcanonical D-branes and Back Reaction

We compare the emission rates from excited D-branes in the microcanonical ensemble with back reaction corrected emission rates from black holes in field theory. In both cases, the rates in the high energy tail of the spectrum differ markedly from what a canonical ensemble or free field theory approach would yield. Instead of being proportional to a Bose-Einstein distribution function, the rates in the high energy tail are proportional to eBH , where ∆SBH is the difference in black hole entropies before and after emission. After including the new effects, we find agreement, at leading order, between the D-brane and field theory rates over the entire range of the spectrum. 1 Work supported in part by a DOE grant DE-FG03-92-ER40701. 2 Work supported in part by a DOE grant DE-FG03-92-ER40701 and by a DuBridge Fellowship.