Conditions for Quantum Violation of Macroscopic Realism

Author(s)
Johannes Kofler, Caslav Brukner
Abstract

Why do we not experience a violation of macroscopic realism in everyday life. Normally, no violation can be seen either because of decoherence or the restriction of coarse-grained measurements, transforming the time evolution of any quantum state into a classical time evolution of a statistical mixture. We find the sufficient condition for these classical evolutions for spin systems under coarse-grained measurements. However, there exist "nonclassical" Hamiltonians whose time evolution cannot be understood classically, although at every instant of time the quantum state appears as a classical mixture. We suggest that such Hamiltonians are unlikely to be realized in nature because of their high computational complexity.

Organisation(s)
Quantum Optics, Quantum Nanophysics and Quantum Information
Journal
Physical Review Letters
Volume
101
No. of pages
4
ISSN
0031-9007
DOI
https://doi.org/10.1103/PhysRevLett.101.090403
Publication date
2008
Peer reviewed
Yes
Austrian Fields of Science 2012
103026 Quantum optics
Portal url
https://ucrisportal.univie.ac.at/en/publications/068dd5af-001a-4909-89a7-af18bc7221bd