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P. Thomann

Publications and source records attributed to P. Thomann.

2 recordsLinked to original sources

Continuity and anomalous fluctuations in random walks in dynamic random environments: numerics, phase diagrams and conjectures

We perform simulations for one dimensional continuous-time random walks in two dynamic random environments with fast (independent spin-flips) and slow (simple symmetric exclusion) decay of space-time correlations, respectively. We focus on the asymptotic speeds and the scaling limits of such random walks. We observe different behaviors depending on the dynamics of the underlying random environment and the ratio between the jump rate of the random walk and the one of the environment. We compare our data with well known results for static random environment. We observe that the non-diffusive regime known so far only for the static case can occur in the dynamic setup too. Such anomalous fluctuations give rise to a new phase diagram. Further we discuss possible consequences for more general static and dynamic random environments.

math.PR

On the stability of optical lattices

In this article, we present an analysis of the stability of optical lattices. Starting with the study of an unstable optical lattice, we establish a necessary and sufficient condition for intrinsic phase stability, and discuss two practical solutions to fulfill this condition, namely minimal and folded optical lattices. We then present a particular example of two-dimensional folded optical lattice which has the advantage of being symmetric, power recycling and having a convenient geometry. We have used this lattice for laser collimation of a continuous cesium beam in a fountain geometry.

physics.atom-ph