Physics with many positrons : Varenna on Lake Como, Villa Monastero, 7-17 July 2009

With the exception of positron emission tomography (PET), the field of low energy positron science produces relatively few academic articles each year compared to more accessible fields. Though much has been achieved since the publication of two related volumes earlier in this series: Positron Solid State Physics (1981) and Positron Spectroscopy of Solids (1993), only the first steps have been made towards 'physics with many positrons': physical situations where the interactions of positrons with positrons can be observed. This 2009 "Enrico Fermi School" aims to stimulate the field of positron research as a whole, and particularly those facilities which will make positrons more readily available, at higher intensities and spatial and temporal densities. The prospect of making a positronium Bose-Einstein condensate, observing stimulated annihilation or producing an annihilation gamma ray laser hold great appeal for many researchers working in the field. The book is in two parts. The first presents recent results and speculations regarding future experiments where positron-positron interaction is an essential factor, as well as experiments with single positrons which nevertheless require positron storage or intense primary sources. The second part focuses on the production of high positron fluxes and densities. The progress envisioned with positron traps is thoroughly discussed in the final chapters. It is hoped that this book will encourage a greater number of users, increase the volume of useful results and possibly lead to future breakthroughs which will both capture the imagination and elucidate the underlying nature of the physical world.