The average drift velocity of a polymer chain due to an applied electric field is calculated in the Rubinstein-Duke model for reptation. Imposing periodic boundary conditions on the reptating chain the stationary state is solved exactly from the master equation, and the drift velocity is...

Recently constructed models for reptation such as the Rubinstein-Duke model are discussed in relation to electrophoresis. A full solution for the probability distribution for the steady state is given for the case of periodic boundary conditions. The model is modified by allowing only for single...

A simplified model of reptation is presented. The Master Equation of the model is systematically solved by expansion in powers of the strength of the driving field. From the explicit form of the probability distribution, exact conclusions can be drawn about the average shape of the polymer, its...

A fluid interface near a critical point is commonly pictured as an intrinsic interface broadened by thermally excited capillary waves. A comparison of the capillary-wave theory with experiments is hampered by the presence of two short-wavelength cutoff parameters in the theory. We review a...

Critical singularities disappear in systems placed in an inhomogeneous field that couples with the order parameter. On the basis of simple renormalization arguments we show that the change from singular behavior in the absence of a field to nonsingular behavior in the presence of a field is...

The paper deals with the question how critical fluctuations in gases are affected by the presence of a gravitational field. We have investigated the effects of gravity using a squared-gradient approximation for the free energy density. It is found that the order-parameter correlation function...

The influence of gravity on the suppression of the capillary fluctuations of a liquid-vapour interface is studied by simulating a Lennard-Jones system in two dimensions in a gravity like field. The results are compared to the capillary wave theory. A lower length cut-off is found for the...

The gravitational field induces density gradients in gases near the critical point. These density gradients are usually evaluated with the assumption that the relationship between the local density and local chemical potential is the same as for a macroscopic system in thermodynamic equilibrium....

Critical phenomena in an Ising-like spin system on a triangular lattice are studied by means of the renormalization theory. The critical indices of the critical point due to triplet interactions are determined approximately, in fair agreement with the exponents, known from the exact solution due...

We have simulated a liquid-vapor interface which is confined by two parallel walls. Initially, a liquid slab is positioned perpendicular to the walls. The liquid-vapor interface deforms to a cylindrical surface which makes a definite contact angle with the walls. The angle could be varied...