  We study the quantum effects of Near-Extremal black holes near their
horizons. The gravitational dynamics in such backgrounds are closely connected
to a particle in $AdS_2$ with constant electric field. We use this picture to
solve the theory exactly. We will give a formula to calculate all correlation
functions with quantum gravity backreactions as well as the exact
Wheeler-DeWitt wavefunction. Using the WdW wavefunction, we investigate the
complexity growth in quantum gravity.
