LAUSR

We study the Hawking radiation on the quantum space-time generated by a quantum ingoing null shell in the 2d theory of quantum gravity proposed by Callan-Giddings-Harvey-Strominger (CGHS). The quantum space-time is a superposition of classical geometries with uncertainty in position and momentum of the collapsing shell. The Hawking radiation spectrum is computed, revealing a non-thermal behaviour for finite time as well as a dependence on the shell’s physical degrees of freedom. Hawking radiation’s dependence on the collapsing shell becomes irrelevant in the late time approximation as the temperature depends exclusively on the cosmological constant. When quantum corrections are taken into account, the profile of the Hawking radiation as a function of time contains information about the initial state of the collapsing shell. The energy flux of 2d black hole radiation is computed explicitly and is shown to coincide with small differences due to the approximations required for an explicit computation with the standard results derived taking into account the conformal anomaly