WAVE-FUNCTION COLLAPSE BY MEASUREMENT AND ITS SIMULATION - REPLY

We discuss and clarify the concept of dephasing in the many-Hilbert-sp ace approach to the quantum measurement problem. We argue that the pha se randomization provoked by a detecting macroscopic device is respons ible for the loss of quantum coherence, and that the ''collapse of the wave function'' is to be regarded as a statistical process for the ac cumulated distribution over many events. In stressing the fundamental differences between our approach and the Copenhagen interpretation, we counter the objections put forward by Johnston [preceding Comment, Ph ys. Rev. A 48, 2497 (1993)], whose stand-point is essentially similar to the Copenhagen one.