We develop notions of a representation of a topological graph E and of a covariant representation of a topological graph E which do not require the machinery of C∗-correspondences and Cuntz– Pimsner algebras. We show that the C∗-algebra generated by a universal representation of E is isomorphic to the Toeplitz algebra of Katsura’s topological-graph bimodule, and that the C∗-algebra generated by...

Poisson brackets that are spacetime covariant are presented for a variety of relativistic field theories. These theories include electromagnetism, general relativity, and general relativistic fluids and plasmas in Eulerian representation. The examples presented suggest the development of a general theory; the beginnings of such a theory are presented. Our covariant bracket formalism provides a ...

The role of the contribution from the fermion mass term in the axial vector Ward identity in generating the U(1) axial anomaly, both local and global, is elucidated. Gauge invariance requires the fermion to decouple from the gauge field if it is very heavy. This identifies the Adler-Bell-Jackiw (ABJ) anomaly with the asymptotic limit of the sign reversed mass term. In an instanton background, t...

In this paper, we define the concept of Jacobi forms of half-integral weight using Takase’s automorphic factor of weight 1/2 for a two-fold covering group of the symplectic group on the Siegel upper half plane and find covariant maps for the SchrödingerWeil representation. Using these covariant maps, we construct Jacobi forms of half integral weight with respect to an arithmetic subgroup of the...

Covariant phase difference observables are determined in two different ways, by a direct computation and by a group theoretical method. A characterization of phase difference observables which can be expressed as difference of two phase observables is given. Classical limit of such phase difference observables are determined and the Pegg-Barnett phase difference distribution is obtained from th...

We construct covariant coordinate transformations on the fuzzy sphere and utilize these to construct a covariant map from a gauge theory on the fuzzy sphere to a gauge theory on the ordinary sphere. We show that this construction coincides with the Seiberg-Witten map on the Moyal plane in the appropriate limit. The analysis takes place in the algebra and is independent of any star-product repre...

We suggest a simple and presumably general procedure to construct formal transformations from (Lie) group covariant Heisenberg algebras into quantum group covariant ones by using Drinfel’d twist. The procedure is successfully applied to general triangular deformations of Lie groups and to the quantum group Uqsl(2). Some consequences at the representation level, focusing on the statistics issue,...

The observable algebra O of SOq(3)-symmetric quantum mechanics is generated by the coordinates Pi and Xi of momentum and position spaces (which are both isomorphic to the SOq(3)-covariant real quantum space IR 3 q). Their interrelations are determined with the quantum group covariant differential calculus. For a quantum mechanical representation of O on a Hilbert space essential self-adjointnes...