Slowing Down of Neutrons in Infinite Homogeneous Media

Slowing down and reflection of waves in truncated periodic media

We consider wave propagation and scattering governed by one dimensional Schrödinger operators with truncated periodic potentials. The propagation of wave packets with narrow frequency supports is studied. The goal is to describe potentials for which the group velocity (for periodic problem) is small and the transmission coefficient for the truncated potential is not too small, i.e. to find medi...

Instability Analysis of Miscible Displacements in Homogeneous Porous Media

Critical slowing down in polynomial time algorithms.

Combinatorial optimization algorithms that compute exact ground states for disordered magnets are seen to exhibit critical slowing down at zero temperature phase transitions. Using the physical features of the models, such as vanishing stiffness on one side of the transition and the ground state degeneracy, the number of operations needed in the push-relabel algorithm for the random field Ising...

Critical slowing down in random anisotropy magnets

We study the purely relaxational critical dynamics with non-conserved order parameter (model A critical dynamics) for three-dimensional magnets with disorder in a form of the random anisotropy axis. For the random axis anisotropic distribution, the static asymptotic critical behaviour coincides with that of random site Ising systems. Therefore the asymptotic critical dynamics is governed by the...

The removal of critical slowing down

J. Brannicka, R. C. Browerbc, S. F. McCormicke, T. A. Manteuffele, J. C. Osbornbd and C. Rebbibc a Department of Mathematics, The Pennsylvania State University, 221 McAllister Building, University Park, PA 16802, USA b Center for Computational Science, Boston University, 3 Cummington St, MA 02215, USA c Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA d A...