Simple Model Systems

Rainer Dick

Rainer Dick

Rainer Dick

Jennifer G. Loeser, HERSCHEL A. RABITZ, Andrew E. DePristo +1 more

A simple model for inelastic scattering may be obtained by suitably generalizing scattering from a square well. The generalization introduces matrices into the quantum-mechanical scattering equations. These equations may be solved exactly to give an explicit expression for the scattering matrix. In this paper we first describe and solve the model, and then discuss the results it predicts for a simple example. We will see that even a simple inelastic system can exhibit rich scattering behavior.

Carsten Lippe, Tanita Klas, Jana Bender +3 more

Scientific advance is often driven by identifying conceptually simple models underlying complex phenomena. This process commonly ignores imperfections which, however, might give rise to non-trivial collective behavior. For example, already a small amount of disorder can dramatically change the transport properties of a system compared to the underlying simple model. While systems with disordered potentials were already studied in detail, experimental investigations on systems with disordered hopping are still in its infancy. To this end, we experimentally study a dipole-dipole-interacting three-dimensional Rydberg system and map it onto a simple XY model with random couplings by spectroscopic evidence. We discuss the localization-delocalization crossover emerging in the model and present experimental signatures of it. Our results demonstrate that Rydberg systems are a useful platform to study random hopping models with the ability to access the microscopic degrees of freedom. This will allow to study transport processes and localization phenomena in random hopping models with a high level of control.

Carl Wieman

Learning Goal: Be able to describe a physical situation that would correspond to simple potential energy curves. Given a simple physical system, be able to draw the relevant potential energy curve needed to model dynamical behaviour. Explain why models are useful in physics.