The permanent spatial decomposition of the wave function

摘要

Permanent spatial decomposition (PSD) is the (hypothesized) property of thewave function of a macroscopic system of decomposing into localized permanentlynon-overlapping parts when it spreads over a macroscopic region. The typicalexample of this phenomenon is the measurement process, in which the wavefunction of the laboratory (quantum system + apparatus + environment)decomposes into n parts, corresponding to the n outcomes of the measurement:the parts are non-overlapping, because they represent a macroscopic pointer indifferent positions, and they are permanently non-overlapping due to theirreversible interaction with the environment. PSD is often mentioned in theliterature, but until now no formal definition or systematic study of thisphenomenon has been undertaken. The aim of this paper is to partially fill thisgap by giving a formal definition of PSD and studying its possible connectionwith scattering theory. The predictive and explanatory powers of thisphenomenon are also discussed and compared with those of Bohmian mechanics.