Quantum path distributions for high-order harmonics in rare gas atoms

We present quantum path distributions of high-order harmonics produced by rare gas atoms interacting with an intense 810 nm laser field, obtained by numerical integration of the time-dependent Schr\"odinger equation within the single active electron approximation. We find that the distributions are sensitive to the atomic potentials, and differ from the distributions predicted by the strong field approximation. We demonstrate that these differences can lead to significant differences in the time-frequency behavior of the harmonics produced in a macroscopic nonlinear medium.