Decoherence: A Closed-System Approach

Abstract

The aim of this paper is to review a new perspective about decoherence, according to which formalisms originally devised to deal just with closed or open systems can be subsumed under a closed-system approach that generalizes the traditional account of the phenomenon. This new viewpoint dissolves certain conceptual difficulties of the orthodox open-system approach but, at the same time, shows that the openness of the quantum system is not the essential ingredient for decoherence, as commonly claimed. Moreover, when the behavior of a decoherent system is described from a closed-system perspective, the account of decoherence turns out to be more general than that supplied by the open-system approach, and the quantum-to-classical transition defines unequivocally the realm of classicality by identifying the observables with classical-like behavior.

Quantum state reduction: Generalized bipartitions from algebras of observables

“…Along the same lines, in a series of papers (e.g. [29][30][31][32]; see also [33]) Castagnino, Lombardi, and collaborators have developed the self-induced decoherence (SID) program, which conceptualizes decoherence as a dynamical process which identifies the classical variables by inspection of the Hamiltonian, without the need to explicitly identify a set of environment degrees of freedom. The variational approach we sketch in Section 7 is similarly concerned with the dynamical selection of a preferred set of observables.…”

The Correspondence Principle and the Understanding of Decoherence

“…When understood as a coarse evolution, as in the case of classical irreversibility, decoherence may happen in closed systems regarding certain relevant observables (this closed-system view leads to a generalized view of decoherence, see Castagnino 2014, Fortin andLombardi 2016).…”

Quantum Decoherence: A Logical Perspective

“…According to the work of our group, the different approaches to decoherence can be described from a General Theoretical Framework for Decoherence consisting of 3 steps [6] [8] [36] [37]. The most important step is to choose a subset of the observables of interest.…”