The electrons are subject to a given time independent ... the Von-Neumann equation at the boundary of the quantum region Q, we ... modified potential V which coincides with V in Q and which is constant in C: .... (15) g(6, p, t) = R(-p) 96(-p,t â T(-p)) +T(-p) ga(Pa (p), t â T(-p)), p > 0. 6 ..... be a test function in D (R, XR, X R ).