The recent survey by M. Schlosshauer, titled "Quantum decoherence," published in Physics Reports (2019), critically examines the role of decoherence in the quantum measurement problem. The review asserts that while decoherence influences the statistics of measurement outcomes, it does not provide a substantial solution to the measurement problem itself. Schlosshauer emphasizes that decoherence must be understood in an interpretation-independent manner, particularly in its relation to classical concepts as discussed in Section 7.3, which addresses Niels Bohr's perspectives. The review highlights the limitations of decoherence in addressing foundational issues in quantum mechanics.
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Maximilian Schlosshauer said:One of the central topics in the foundations of quantum mechanics is known as the quantum measurement problem, and in Sec. 7.1 below we will discuss whether decoherence has anything of substance to say about it. In Sec. 7.2, we will then briefly review the role that decoherence plays, or may play, in the various interpretations of quantum mechanics. In Sec. 7.3, we will comment on Niels Bohr’s views on the primacy of classical concepts and their relationship to the quantum–classical correspondence described by decoherence.
In Section 7.1 said:for the kinds of entangled quantum states produced by decoherence-type interactions to be interpreted as describing a situation in which the system becomes “classical,” we need to take the existence of measurement outcomes as a priori given, or otherwise give an account outside of decoherence of how measurement outcomes are produced, because the property of classicality is ultimately a statement about measurement statistics. Thus decoherence, by itself, cannot address the measurement problem in any substantial way.
Of course, to say that decoherence has no bearing on the measurement problem—or on any of the “big” foundational problems in general—is not to suggest that decoherence and its underlying ideas cannot be of relevance in the investigation of fundamental questions. [...] the ability of decoherence to dynamically define preferred bases is exploited in certain interpretations of quantum mechanics
It is carefully written to be interpretation-independent:Demystifier said:Is there anything new in this review in comparison with his older review on decoherence and his book?
Section 7.3 on the relation to Bohr's view is also new.Maximilian Schlosshauer (p.3) said:Stated in general and interpretation-neutral terms, decoherence describes how entangling interactions with the environment influence the statistics of future measurements on the system.