The motion of Charge-Density Waves (CDWs) shows many similarities with transport in superconductors with the role of voltage and current reversed. Submicron superconducting devices are very important in both fundamental studies and applications of superconductivity. For CDWs, reliable fabrication methods for making similar devices are not as advanced and are still being developed. In search for new mesoscopic CDW physics, we have fabricated insulating longitudinal point contacts and weak links in the CDW conductor NbSe 3.

The most efficient known method for solving certain computational problems is to construct an iterated map whose fixed points are by design the problem's solution. Although the origins of this idea go back at least to Newton, the clearest expression of its logical basis is an example due to Mermin. A contemporary application in image recovery demonstrates the power of the method.

We identify the shortcomings of existing ab initio quantum chemistry calculations for the hyperfine couplings in the recently characterized azafullerene, C59N. Standard gaussian basis sets in the context of all-electron calculations are insufficient to resolve the spin density near the cores of the atoms. Using the projector augmented wave (PAW) method implemented on top of a standard pseudo-potential plane-wave density-functional framework, we compute significantly more accurate values for the Fermi contact interaction. © 2002 Elsevier Science B.V. All rights reserved.

Under certain circumstances, decreasing the dimensions of a material may lead to elastic or anelastic properties that diverge from bulk behavior. A distinction is made between elastic deformation, for which bond rearrangements are not required, and anelastic behavior, which involves reversible deformation due to defect motion. Elastic deformation (due to bond stretching) remains structure-insensitive down to near-atomic length scales, and only small deviations are expected (of the order of 10%).

We present experimental results on the snap-off dynamics of a drop with viscosity λη dripping through a fluid of viscosity η. This paper focuses on the Stokes regime where both the inner and outer fluid viscous stresses are balanced by the pressure gradients arising from the interfacial curvature. We track the time dependence of the drop profiles near snap-off and find that successive profiles can be rescaled onto a single curve. We explore the dependence of this scaling on the nozzle diameter, surface tension, density mismatch, and viscosity ratio λ.

The level set of an elliptic function is a doubly periodic point set in ℂ. To obtain a wider spectrum of point sets, we consider, more generally, a Riemann surface S immersed in ℂ2 and its sections ("cuts") by ℂ. More specifically, we consider surfaces S defined in terms of a fundamental surface element obtained as a conformai map of triangular domains in ℂ. The discrete group of isometries of ℂ2 generated by reflections in the triangle edges leaves S invariant and generalizes double-periodicity.

The Peierls stress for a [111]-screw dislocation in bcc Tantalum is calculated using an embedded atom potential. More importantly, a method is presented which allows accurate calculations of the Peierls stress in the smallest periodic cells. This method can be easily applied to ab initio calculations, where only the smallest unit cells capable of containing a dislocation can be conviently used. The calculation specifically focuses on the case where the maximum resolved shear stress is along a 110-plane.

A recent proposal by Maris, 1 that single electron bubbles in helium might fission into separate, particle-like entities, does not properly take into account the failure of the adiabatic approximation when, due to tunneling, there is a long electronic time scale. The point along the fission pathway of a photoexcited p-state bubble, where the adiabatic approximation first breaks down, occurs well before the bubble waist has pinched down forming two cavities.

How ab initio numerical simulation methods can be used to check and improve structure models for i(Al-Pd-Mn) is presented. By focusing on the optimization of a small approximant, a number of general structural and compositional rules simple enough to be applicable to the quasicrystalline structure were obtained.

We introduce a growth model for entropically stabilized quasicrystals. The dominating feature of this model is a fluctuating growth front which enables growth near equilibrium with small phason components. We summarize the results obtained for 2D and give a first presentation of 3D calculations.