Classical World Arising out of Quantum Physics under the Restriction of CoarseGrained Measurements
Abstract
Conceptually different from the decoherence program, we present a novel theoretical approach to macroscopic realism and classical physics within quantum theory. It focuses on the limits of observability of quantum effects of macroscopic objects, i.e., on the required precision of our measurement apparatuses such that quantum phenomena can still be observed. First, we demonstrate that for unrestricted measurement accuracy, no classical description is possible for arbitrarily large systems. Then we show for a certain time evolution that under coarsegrained measurements, not only macrorealism but even classical Newtonian laws emerge out of the Schrödinger equation and the projection postulate.
 Publication:

Physical Review Letters
 Pub Date:
 November 2007
 DOI:
 10.1103/PhysRevLett.99.180403
 arXiv:
 arXiv:quantph/0609079
 Bibcode:
 2007PhRvL..99r0403K
 Keywords:

 03.65.Ta;
 Foundations of quantum mechanics;
 measurement theory;
 Quantum Physics
 EPrint:
 4 pages, 1 figure, second revised and published version