preprint numerics no. 3/2008 norwegian university of science and technology trondheim, norway We present a new method for tracking an interface immersed in a given velocity field. The method is particularly relevant to the simulation of unsteady free surface problems using the arbitrary Lagrangian-Eulerian (ALE) framework. The new method has been constructed with two goals in mind: (i) to be ab...

We discuss issues concerning M(atrix) theory compactifications on curved spaces. We argue from the form of the graviton propagator on curved space that excited string states do not decouple from the annulus D0-brane v amplitude, unlike the flat space case. This argument shows that a large class of quantum mechanical systems with a finite number of degrees of freedom cannot reproduce supergravit...

We discuss issues concerning (M)atrix model compactifications on curved spaces. We argue from the form of the graviton propagator on curved space that excited string states do not decouple from the annulus D0-brane v amplitude, unlike the flat space case. This argument shows that a large class of quantum mechanical systems with a finite number of degrees of freedom cannot reproduce supergravity...

ALE and Taub-NUT (or ALF) hyper-Kahler four-manifolds can be naturally constructed as hyper-Kahler quotients. In the ALE case, this construction has long been understood in terms of D-branes; here we give a D-brane derivation in the Taub-NUT case. Likewise, instantons on ALE spaces and on Taub-NUT spaces have ADHM-like constructions related to hyper-Kahler quotients. Here we refine the analysis...

The aim of this paper is to study the feasibility of using (irreversible) entropy production as driving force for a moving mesh. Such a method should be able to capture or track physical phenomena such as viscous and thermal boundary layers, shock waves and regions with chemical reactions. A brief outline is given for the FEM-ALE approach, which forms the basis of the moving mesh method. Mesh v...