Quantum mechanics (QM) is equivalently reformulated in the form of a Poisson system on the phase space consisting of density matrices, where the " observables " , as well as " symmetry generators "… (More)

The topology of the embedding of the coadjoint orbits of the unitary group U of an infinite dimensional complex Hilbert space H, as canonically determined subsets of the space Ts of symmetric… (More)

Proposals for nonlinear extenstions of quantum mechanics are discussed. Two different concepts of “mixed state” for any nonlinear version of quantum theory are introduced: (i) genuine mixture… (More)

In carefully worded paper buz1, the authors tried to derive linearity (i.e. affinity on ‘density matrices’ =: DM) and complete positivity (CP) of general quantum mechanical dynamics g from usual… (More)

It is shown how nonlinear versions of quantum mechanics can be refolmulated in terms of a (linear) C∗-algebraic theory. Then also their symmetries are described as automorphisms of the correspondong… (More)