2+1 gravity for genus >1

In [1] we analysed the algebra of observables for the simple case of a genus 1 initial data surface ² for 2+1 De Sitter gravity. Here we extend the analysis to higher genus. We construct for genus 2 the group of automorphismsH of the homotopy group ₁ induced by the mapping class group. The groupH induces a groupD of canonical transformations on the algebra of observables which is related to the braid group for 6 threads.     

The monodromy rings of one loop Feynman integrals

The monodromy rings of Feynman integrals for one loop graphs with an arbitrary number of lines are determined.Research sponsored by the National Science Foundation, Grant No. GP-16147.     

Improved Hamiltonian for general relativity

A Hamiltonian formalism for asymptotically flat spaces in general relativity which is manifestly covariant under Poincaré transformations at infinity is proposed and some of its implications are briefly discussed.     

Band hybridization in rotational motion

The back-bending behaviour of the moment of inertia as a function of the square of the angular velocity, for the ground-, and ß-rotational trajectories in ₆₆¹⁵⁶Dy₉₀, is described in terms of band hybridization.