  We describe a model for unitary black hole evaporation with no information
loss in terms of a quantum computation. We assume that there is a fine tuned
interaction between the qubits of the black hole Bell states which is the
inverse of premeasurement. Evaporation is unitary due to a projection on the
black hole state at the end of each computation whereas information comes out
of the black hole by teleportation. The model requires only four operations;
the qubit interactions, the Hadamard and CNOT gates and the projection which is
nonunitary. The model is a concrete quantum computation that realizes the final
black hole state idea with some modifications.
