Exact Partition Functions for Gauge Theories on ${\mathbb{R}}_{\lambda }^3$

The noncommutative space ${\mathbb{R}}_{\lambda }^3$, a deformation of ${\mathbb{R}}^3$, supports a $3$-parameter family of gauge theory models with gauge-invariant harmonic term, stable vacuum and which are perturbatively finite to all orders. Properties of this family are discussed. The partition function factorizes as an infinite product of reduced partition functions, each one corresponding to the reduced gauge theory on one of the fuzzy spheres entering the decomposition of ${\mathbb{R}}_{\lambda }^3$. For a particular sub-family of gauge theories, each reduced partition function is exactly expressible as a ratio of determinants. A relation with integrable 2-D Toda lattice hierarchy is indicated.