Nonequilibrium fluctuations in μ space

The properties of fluctuations in space in or outside thermal equilibrium are obtained by solving hierarchies of equations derived either from the Liouville or the Master equation. In particular we study the one-, two-, etc., time correlation functions that describe the spatial and temporal behavior of the fluctuations in space. Explicit solutions are obtained for a dilute gas. The Langevin approach is briefly discussed. Our results are compared with those obtained in the extensive literature, which is reviewed in some detail.     

New symmetry properties of a class of Hubbard models

In the Hubbard model for crystals of the AB-type all information on the system is already contained in the set of eigenstates where the number of sites equals the number of electrons or exceeds it by one. We prove this by deriving relations among the eigenstates with different numbers of particles which do not rely on the well-known transformation of electrons to holes. In this context a new good quantum number is identified. We report on results for the one-dimensional case.     

On the occasion of being awarded the title of doctor honoris causa at the university of montpellier II

Abstract

Je suis très honoréde recevoir le titre de Docteur Honoris Causa de 1 Université de Montpellier, une des Universités les plus anciennes et les plus prestigieuses de France et d'Europe. Je considère que c′est une preuve de genérosité de la part des autorités de I'Université que d'honorer quelqu'un qui a une lacune manifeste. En efet, si je parle, je préfére I'anglais. Si je pense, je le fais naturellement en allemand. Et sije me tais, c'est souvent en français. J'espére que le grand honneur que l'on me fait ne va donc pas à l'encontre de la constitution française.

Vous savez, aujourd'hui, il est trés facile de communiquer par Fax et e-mail. Mais, sans une langue commune, aucune communication n'est possible. Heureusement, les scientifiques ont inventé des langues formelles et logiques comme le FORTRAN et le C++. Mais ces langues ne suflsent pas pour exprimer la gratitude que J'éprouve à être ici, dans une robe magnijique et unique. Je suis persuadé que j'ai fini par éveiller l'admiration de ma chère epouse et peut-être aussi le respect de quelques personnes présentes dans cette vénérable salle. Mais pour exprimer quelques pensées plus sérieuses, “Lmore earnest”, il me faut changer ma langue muette contre ma langue parlante, l'anglais.     

New measurements of Cabibbo-suppressed decays of mesons with the CLEO-c detector

Using of data collected with the CLEO-c detector, we report on first observations and measurements of Cabibbo-suppressed decays of D mesons in the following six decay modes: pi+ pi- pi0 pi0, pi+ pi+ pi- pi- pi0, pi+ pi0 pi0, pi+ pi+ pi- pi0, eta pi0, and omega pi+ pi-. Improved branching fraction measurements in eight other multipion decay modes are also presented. The measured D --> pi pi rates allow us to extract the ratio of isospin amplitudes A(DeltaI = (3/2) / A(DeltaI = (1/2)) = 0.420 +/- 0.014(stat) +/- 0.016(syst) and the strong phase shift of delta1 = (86.4 +/- 2.8 +/- 3.3) degrees, which is quite large and now more precisely determined.     

Biased lattice gases with correlated equilibrium states

The approach to and structure of the equilibrium state is studied for a 7-bit lattice gas with biased forward and backward transition rates by means of mean field theory and computer simulations. If the rate constants obey the factorizability and the detailed balance conditions, the occupations of different velocity directions are uncorrelated, anH-theorem is valid, and a nonuniversal equilibrium state exists that depends explicitly on the transition rates. In case the above conditions are not satisfied, theH-theorem is no longer valid, and mean field theory also predicts nontrivial velocity correlations in postcollision states. The simulations are mainly concentrated on the time dependence of pre- and postcollision velocity correlations on a single node, and on slowly increasing fluctuations that might indicate metastable behavior.