Contrary to previous claims, it is shown that the expectation values of the quantum stress tensor for a massless scalar field propagating on a two-dimensional extreme Reissner-Nordstrom black hole are indeed regular on the horizon.
Balbinot, R. Fagnocchi, S. Fabbri, A. Farese, Sara Navarro Salas, José 2004 On the quantum stress tensor for extreme 2d Reissner-Nordstrom black holes Physical Review D 70 6 064031-1 064031-5
