Quantum reflection, evaporation, and transport currents at 4He surfaces

In this work, we study-transport currents in excited states. This requires the calculation of particle currents < n vertical bar j vertical bar n > to second order in the excitation amplitudes. For that purpose, we take a well-tested microscopic theory of inhomogeneous quantum liquids and extend it to find the mass currents created when atoms scatter off a surface or when excitations evaporate atoms. This is the first theoretical study of transport phenomena in a quantum liquid based on a quantitative microscopic theory.