An Exposition of the Connection between Limit-Periodic Potentials and Profinite Groups

We classify the hulls of different limit-periodic potentials and show that the hull of a limit-periodic potential is a procyclic group. We describe how limit-periodic potentials can be generated from a procyclic group and answer arising questions. As an expository paper, we discuss the connection between limit-periodic potentials and profinite groups as completely as possible and review some recent results on Schroedinger operators obtained in this context

A Novel Optical Package for ATLAS Pixel Detector

An optical package of novel design has been developed for the ATLAS pixel detector. The package contains two VCSELs and one PIN diode to transmit and receive optical signals. The design is based on a simple connector-type concept and is made of radiation-hard material. Several packages have been fabricated and show promising results.Comment: 3 pages, 1 figure, to be published in Proc. of the 2000 Annual Meeting of the Division of Particles and Fields of the American Physical Society, Columbus, Ohi