We present a new procedure which allows a coherent state (CS) quantization of any set with a measure. It is manifest through the replacement of classical observables by CS quantum observables, which acts on a Hilbert space of prescribed dimension N . The algebra of CS quantum observables has the finite dimension N 2 . The application to the 2-sphere provides a family of inequivalent CS quantizations, based on the spin spherical harmonics (the CS quantization from usual spherical harmonics appears to give a trivial issue for the cartesian coordinates). We compare these CS quantizations to the usual (Madore) construction of the fuzzy sphere. The difference allows us to consider our procedures as the constructions of new type of fuzzy spheres. The very general character of our method suggests applications to construct fuzzy versions of a variety of sets.
Some ideas on quantizationA classical description of a set of data, say X, is usually carried out by considering sets of real or complex functions on X. Depending on the context (data handling, signal analysis, mechanics. . . ) the set X will be equipped with a definite structure (topological space, measure space, symplectic manifold. . . ) and the set of functions on X which will be considered as classical observables must be restricted with regard to the structure on X; for instance, signals should be square integrable with respect to the measure assigned to set X.How to provide instead a "quantum description" of the same set X? As a first characteristic, the latter replaces -this is a definition -the classical observables by quantum observables, which do not commute in general. As usual, these quantum observables will be realized as operators acting on some Hilbert space H, whose projective version will be considered as the set of quantum states. This Hilbert space will be constructed as a subset in the set of functions on X.The advantage of the coherent states (CS) quantization procedure, in a standard sense [1,2,3] as in recent generalizations [4] and applications [5] is that it requires a minimal significant structure on X, namely the only existence of a measure µ(dx), together with a σ-algebra of measurable subsets. As a measure space, X will be given the name of an observation set in the present context, and the existence of a measure provides us with a statistical reading of the set of measurable real or complex valued functions on X: computing for instance average values on subsets with bounded measure. The quantum states will correspond to measurable and square integrable functions on the set X, but not all square integrable functions are eligible as quantum states. The construction of H is equivalent to the choice of a class of eligible quantum states, together with a technical condition of continuity. This provides a correspondence between classical and quantum observables by defining a generalization of the so-called coherent states.Although the procedure appears mathematically as a quantization, it may also be considered as a change of point ...