Physical Reality and Mathematical Description

This collection of essays is intended as a tribute to Josef Maria Jauch on his sixtieth birthd~. Through his scientific work Jauch has justly earned an honored name in the community of theo retical physicists. Through his teaching and a long line of dis tinguished collaborators he has put an imprint on modern mathema tical physics. A number of Jauch's scientific collaborators, friends and admirers have contributed to this collection, and these essays reflect to some extent Jauch's own wide interests in the vast do main of theoretical physics. Josef Maria Jauch was born on 20 September 1914, the son of Josef Alois and Emma (nee Conti) Jauch, in Lucerne, Switzerland. Love of science was aroused in him early in his youth. At the age of twelve he came upon a popular book on astronomy, and an exam ple treated in this book mystified him. It was stated that if a planet travels around a centre of Newtonian attraction with a pe riod T, and if that planet were stopped and left to fall into the centre from any point of the circular orbit, it would arrive at the centre in the time T/I32. Young Josef puzzled about this for several months until he made his first scientific discovery : that this result could be derived from Kepler's third law in a quite elementary way.

Inhalt
I : Art, History and Philosophy.- Science and Art.- Léonard de Vinci et l'hydrodynamique.- Our knowledge of the external world.- Geometrie and Physik.- Quantum physics and process metaphysics.- What happened to our elementary particles? (Variations on a theme of Jauch).- Partons-elementary constituents of the proton?.- Is the zero-point energy real?.- Reflections on Fundamentality and complexity.- II : Mathematical Physics.- Weights on spaces.- A second look at the essential selfadjointness of the Schrödinger operators.- Some absolutely continuous operators.- A remark on the Kochen-Specker theorem.- Die Heisenberg-Weyl'schen Vertauschungsrelationen: Zum Beweis des von Neumannschen Satzes.- Real versus complex representations and linear-antilinear commutant.- III: Scattering Theory and Field Theory.- Approche algébrique de la théoree non-relativiste de la diffusion á canaux multiples.- Fourier scattering subspaces.- N-Particle scattering rates.- Cross sections in the quantum theory of scattering.- On long-range potentials.- Phenomenological aspects of localizability.- Charge distributions from relativistic form factors.- Charges and currents in the Thirring model.- The nonlocal nature of electromagnetic interactions.- Le modèle des champs de jauge unifíes.- Is anti-gravitation possible?.- IV : Quantum Theory and Statistical Mechanics.- On a new definition of quantal states.- The minimal K-flow associated to a quantum diffusion process.- Composite particles in many-body theory.- On the quantum analogue of the Lévy distribution.- Existence and bounds for critical energies of the Hartree operator.- Long range ordering in one-component Coulomb systems.- A scale group for Bolt zmann-type equations.- Effect of a non-resonant electromagnetic field on the frequencies of a nuclear magnetic moment system.