Evaporation of a two-dimensional charged black hole - art. no. 104016

We construct a dilatonic two-dimensional model of a charged black hole. The classical solution is a static charged black hole, characterized by two pa rameters in and q representing the black hole's mass and charge. Then we st udy the semiclassical effects, and calculate the evaporation rate of both m and q, as a function of these two quantities. Analyzing this dynamical sys tem, we find two qualitatively different regimes, depending on the electrom agnetic coupling constant g(A). If the latter is greater than a certain cri tical value, the charge-to-mass ratio decays to zero upon evaporation. On t he other hand, for g(A) smaller than the critical value, the charge-to-mass ratio approaches a non-zero constant that depends on g(A) but not on the i nitial values of m and q.