Classical world arising out of quantum physics under the restriction of coarse-grained measurements

摘要

Conceptually different from the decoherence program, we present a noveltheoretical approach to macroscopic realism and classical physics withinquantum theory. It focuses on the limits of observability of quantum effects ofmacroscopic objects, i.e., on the required precision of our measurementapparatuses such that quantum phenomena can still be observed. First, wedemonstrate that for unrestricted measurement accuracy no classical descriptionis possible for arbitrarily large systems. Then we show for a certain timeevolution that under coarse-grained measurements not only macrorealism but eventhe classical Newtonian laws emerge out of the Schroedinger equation and theprojection postulate.