arXiv subjects
Publications and source records attributed to H. Dieter Zeh.
The role attributed to the observer in various interpretations of quantum mechanics as well as in classical statistical mechanics is discussed, with particular attention being paid to the Everett interpretation. In this context, the important difference between "quasi-classical" (robust against decoherence) and "macroscopically given" (rather than being part of a thermodynamic ensemble) is pointed out.
This is a non-technical presentation (in historical context) of the quantum theory that is strictly based on global unitarity. While the first part was written for a general readership, Sect. 5 may appear a bit provocative. I argue that the single-particle wave functions of quantum mechanics have to be correctly interpreted as field modes that are "occupied once" (that is, first excited states of the corresponding quantum oscillators in the case of a boson field). Multiple excitations lead non-relativistically to apparent many-particle wave functions, while the quantum states proper are defined by wave function(al)s on the configuration space of fundamental fields, or on another, as yet elusive, fundamental basis.
Various interpretations of quantum mechanics, favored (or neglected) by John Bell in the context of his non-locality theorem, are compared and discussed.
In contrast to claims by Barbour, Koslowski and Mercati, their "Janus point solution" does require a very improbable selection condition. While gravitational contraction in an expanding universe may then represent the master arrow of time, it would be insufficient by itself to describe the time asymmetry of the observed world.
Remarks regarding a novel decoherence mechanism [arXiv:1311.1095]. According to this model by itself, "real" (that is, irreversible) decoherence would require some initially present entanglement with the environment.
Rovelli's argument against the realistic interpretation of quantum states and in favor of an ontology of quantum events is refuted.