Proceedings of the Royal Society of London Series A Mathematical and Physical Sciences

Primary state diffusion

Ian Colin Percival

Published Oct 8, 1994• 115 citations

Abstract

Abstract Primary quantum state diffusion (PSD) theory is an alternative quantum theory from which classical dynamics, quantum dynamics and localization dynamics are derived. It is based on four principles, that a system is represented by an operator, its state by a normalized state vector, the state vector satisfies a Langevin-Itô state diffusion equation, and the resultant density operator for an ensemble must satisfy an equation of elementary Lindblad form. There are three conditions. The ז0 first determines the operator, to within an undetermined universal time constant ז0. The second and third conditions put opposing bounds on ז0. Dissipation of coherence is distinguished from destruction of coherence. The state diffusion destroys coherence and produces the localization or reduction that makes classical dynamics possible. PSD theory is a development of the environmental quantum state diffusion theory of Gisin and Percival and particularly resembles earlier proposals by Gisin and by Milburn. It is also related to the spontaneous localization theories of Ghirardi, Rimini and Weber, of Diósi and of Pearle. The non-relativistic PSD theory is of value only for systems which occupy small regions of space. Special relativity is needed for more extended systems even when they contain only slowly moving massive particles. Experiments on coherence lifetimes and matter interferometry are proposed which either measure ז0 or put bounds on it, and which might distinguish between PSD and ordinary quantum mechanics.

DOI: 10.1098/rspa.1994.0135

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