Composite quantum systems can be differently decomposed -- differently structured -- in to subsystems. In classical physics, such structural considerations are typically considered physically artificial--a mathematical artifact.
However, in the quantum mechanical context, the structural considerations bring some classically unknown, non-trivial observations of foundational as well as of interest for certain applications e.g. in quantum information and open quantum systems theory.
This emerging research direction is yet properly to be appreciated. Apparently simple, the basic concepts are sometimes misconstrued. Our approach to the topic can be found here.
On this page we present some basic results, some of which may be surprising. Below is a list of some recent results of our team that are corollaries of the universally valid and complete quantum mechanics.
-- There may be the decoherence-induced classicality for more than one Universe structure -- the so-called Parallel occurrence of decoherence (POD).
The environment selects a preferred
structure for the open (bipartite) systems [for
some realistic models]
Subtleties (event the puzzles!) regarding the concept of complete positivity of the dynamical maps are easy understood by Quantum Structures