The firewall transformation: neither entirely consistent nor exactly canonical!
Bernard Whiting
In order to overcome the firewall problems that arise during the lifetime of a black hole, ‘t Hooft has proposed the “firewall transformation”, which is simultaneously intended; i) to remove half of the degrees of freedom in the description of black hole collapse and evaporation, and ii) to couple in(out)-going momenta to out(in)-going positions. t Hooft’s description of how this comes about seems to involve a number of approximations. Here, we examine this proposal: a) in an appropriate canonical Hamiltonian framework (where we find the set of approximations used are not entirely consistent) for the in/out-going particles alone, as well as b) in an exact sense including the gravitational system, where we find, though not as a relation between canonical variables, results similar to those ‘t Hooft seeks to implement.
