Deformation quantization of the simplest Poisson orbifold

peer reviewed ; Whenever a given Poisson manifold is equipped with discrete symmetries the corresponding algebra of invariant functions or the algebra of functions twisted by the symmetry group can have new deformations, which are not captured by Kontsevich Formality. We consider the simplest example of this situation: R2 with the reflection symmetry Z2. The usual quantization leads to the Weyl algebra. While Weyl algebra is rigid, the algebra of even or twisted by Z2 functions has one more deformation, which was identified by Wigner and is related to Feigin's glλ and to fuzzy sphere. With the help of homological perturbation theory we obtain explicit formula for the deformed product, the first order of which can be extracted from Shoikhet–Tsygan–Kontsevich formality.