Surface excitations in the random phase approximation

Abstract

Density fluctuations in inhomogeneous systems are treated in the RPA using the Kadanoff–Baym Green's function method. In our analysis, the Wigner distribution function plays an important role. Well-known results for surface plasmons in one- and two-component plasmas are very easy to derive. A brief discussion is given of surface modes in systems for which the interaction is of short range.