LAUSR

Petr Slavicek responded: Linear potential is probably the most convenient test case as one can perform all of the calculations analytically (see also the answer to the next question). The use of the delta function constraint can also be justied within a more general semiclassical treatment of an excitation process with arbitrary laser pulse as outlined in ref. 1 (see also older related work in ref. 2 where the problem is discussed for a Gaussian shaped pulse). Here, an excitation Wigner function is introduced which is shown to be a Wigner function of the pulse envelope A(t), multiplied by the unltered Wigner function. For a constant envelope, we end up with the delta function.