We consider linear systems in which some of the variables evolve on a much faster time scale than the remaining ones. By means of a systematic perturbation theory in the time-scale ratio we extract a reduced dynamics in terms of the slow variables only, valid after an initial transient period....

The frequency-dependent electric polarizability of an ion or metallic cluster immersed in a plasma is studied in the framework of Bloch's classical hydrodynamic model. Both bound and free electrons are treated as a classical fluid moving in the potential created by the fixed ion and a uniform...

We consider linear dynamical systems with motions characterized by two different time-scales. In practice the dynamical matrix in the phenomenological equations of motion often exhibits a strong coupling of the slow and fast variables. It is shown on the basis of the Onsager symmetry relations...

It is shown that a proposed analytical expression accurately fits simulation data of Hagen et al. (Physica A 272 (1999) 376) for the rotational velocity autocorrelation function of interacting Brownian particles. The fit is designed for intermediate and long times, but is also quite good at...

The frequency-dependent polarizability of an ion or metallic cluster immersed in a plasma is studied for the model of a uniform sphere with sharp boundary. The electron gas inside and outside the ion or cluster is treated in the framework of Bloch's hydrodynamic model. Due to the coupling to the...

The dielectric function of an electron-ion plasma is studied in quasistatic approximation by use of linear response theory and the technique of cluster expansion. The coherent part of the electromagnetic field is treated classically. A general expression for the susceptibility kernel is derived...

We study thermodynamic systems near equilibrium described by both slow and fast variables. A reduced relaxation matrix for the slow variables can be obtained from the full relaxation matrix by a systematic elimination of the fast variables. When the full relaxation matrix possesses...

The force and torque exerted on a body of arbitrary shape and constitution by a stationary radiation field are in principle given by integrals of Minkowski's stress tensor over a surface surrounding the body. Similarly the absorbed energy is given by an integral of the Poynting vector. These...

We study scalar wave propagation in a disordered static array of spherical scatterers. Due to a hard core repulsion the scatterers do not overlap. The wave is scattered by a δ-function potential at the center of each of the spheres. To this monopole model we apply the previously developed...

We evaluate the hydrodynamic interaction tensors for two spheres of unequal size and for general mixed slip-stick boundary conditions. A method of reflections leads to a series expansion for the diffusion tensors in powers of the inverse distance l−1 between sphere centers and explicit results...