RECOVERY OF INFORMATION FROM BLACK-HOLE RADIATION BY CONSIDERING STIMULATED-EMISSION

We deal with the black hole information-loss paradox by showing that t he stimulated emission component of black hole radiation contains info rmation about the initial state of the system. The nonlocal behavior t hat allows the recovery of information about the matter that falls beh ind the horizon appears in a natural way. We calculate the expectation value and probability distribution of particles at J+ for a nonvacuum initial state. The entropy of the final state is compared to that of a thermal state with the same energy per mode. We find that the inform ation recovered about the initial state increases with the number of r of the initially incoming particles, reaching, for example, over 30% for r = 1000. We point out that recovering information about the initi al state, nevertheless, does not automatically imply the purity of the final state.