Propagation of local decohering action in distributed quantum systems - art. no. 022118

We study propagation of the decohering influence caused by a local measurem ent performed on a distributed quantum system. As an example, the gas of bo sons forming a Bose-Einstein condensate is considered. We demonstrate that the local decohering perturbation exerted on the measured region propagates over the system in the form of a decoherence wave, whose dynamics is gover ned by elementary excitations of the system. We argue that the post-measure ment evolution of the system (determined by elementary excitations) is of i mportance for transfer of decoherence, while the initial collapse of the wa ve function has negligible impact on the regions that are not directly affe cted by the measurement.