We give necessary and sufficient conditions for the existence of weak solutions of a parabolic problem corresponding to the Kolmogorov operators perturbed by a multipolar inverse square potentialdefined on smooth functions where µ in the drift term is a probability density on R N . To this aim we state a weighted Hardy inequality2 2 , with respect to the Gaussian probability measure dµ = µ(x)dx which is the unique invariant measure for Ornstein-Uhlenbeck type operators. We state the optimality of the constant c o and, then, the nonexistence of positive exponentially bounded solutions to the parabolic problem. 2010 Mathematics Subject Classification. 35K15, 35K65, 35B25, 34G10, 47D03. The authors are members of the Gruppo Nazionale per l'Analisi Matematica, la Probabilitá e le loro Applicazioni (GNAMPA) of the Istituto Nazionale di Alta Matematica (INdAM).1 charge located in a finite number of points a 1 , . . . , a n and of n electrons. The Hartree-Fock model describes these systems (see [7]).It is well known that if L = ∆ and V ≤ c |x| 2−ǫ , c > 0, ǫ > 0, then the corresponding initial value problem is well-posed. But for ε = 0 the problem may not have positive solution. In [2] Baras and Goldstein showed that the evolution problem associated to ∆ + V admits a unique positive solution if c ≤ c o (N) := N −2 2 2 and no positive