Martin H. Müser

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A microscopic theory for the ubiquitous phenomenon of static friction is presented. Interactions between two surfaces are modeled by an energy penalty that increases exponentially with the degree of surface overlap. The resulting static friction is proportional to load, in accordance with Amontons's laws. However, the friction coefficient between bare(More)
Self-assembled lamellar structures composed of block copolymers are simulated by molecular dynamics. The response of a bulk system to external shear is investigated, in particular, the average energy, the entropy production, and the stability of the lamellae's orientation. We distinguish two orientations, a parallel orientation in which the normal to the(More)
The problems of ergodicity and internal consistency in the centroid and ring-polymer molecular dynamics methods are addressed in the context of a comparative study of the two methods. Enhanced sampling in ring-polymer molecular dynamics (RPMD) is achieved by first performing an equilibrium path integral calculation and then launching RPMD trajectories from(More)
Using a theoretical approach and computer simulations, we calculate the normal stiffness K(perpendicular) and the transverse stiffness K(parallel) of the interface between two contacting isotropic solids with randomly rough surfaces and Poisson ratio ν. The theoretical predictions for K(perpendicular) agree well with the simulations. Moreover, the(More)
Two methods are compared that are used in path integral simulations. Both methods aim to achieve faster convergence to the quantum limit than the so-called primitive algorithm (PA). One method, originally proposed by Taka-hashi and Imada, is based on a higher-order approximation (HOA) of the quantum mechanical density operator. The other method is based(More)
Discrete sine-Gordon (SG) chains are studied with path-integral molecular dynamics. Chains commensurate with the substrate show the transition from pinning to quantum creep at bead masses slightly larger than in the continuous SG model. Within the creep regime, a field-driven transition from creep to complete depinning is identified. The effects of disorder(More)
Polymer brushes lead to small friction and wear and thus hold great potential for industrial applications. However, interdigitation of opposing brushes makes them prone to damage. Here we report molecular dynamics simulations revealing that immiscible brush systems can form slick interfaces, in which interdigitation is eliminated and dissipation strongly(More)