Coherent States on Hilbert Modules

We generalize the concept of coherent states, traditionally defined as special families of vectors on Hilbert spaces, to Hilbert modules. We show that Hilbert modules over $C^*$-algebras are the natural settings for a generalization of coherent states defined on Hilbert spaces. We consider those Hilbert $C^*$-modules which have a natural left action from another $C^*$-algebra say, $\mathcal A$. The coherent states are well defined in this case and they behave well with respect to the left action by $\mathcal A$. Certain classical objects like the Cuntz algebra are related to specific examples of coherent states. Finally we show that coherent states on modules give rise to a completely positive kernel between two $C^*$-algebras, in complete analogy to the Hilbert space situation. Related to this there is a dilation result for positive operator valued measures, in the sense of Naimark. A number of examples are worked out to illustrate the theory

Position and momentum observables on R and on R^3

We characterize all position and momentum observables on R and on R^3. We study some of their operational properties and discuss their covariant joint observables.Comment: 18 page

Pionsko-nukleonski član sigma u linearnom sigma modelu

We apply the linear sigma model to analyze pion-nucleon sigma-term. Analytic expresions for these quantities are obtained in terms of the parameters of low-energy physics (pion decay constant and the pion mass). Good results have been obtained in comparison with author\u27s previous work and with other models.Primijenili smo linearni sigma model u analizi pionsko-nukleonskog člana sigma. Analitički izrazi za te veličine izvode se na osnovi parametara nisko-energijske fizike (konstanta raspada i masa piona). Postigli smo dobre ishode u usporedbi s autorovim ranijim radovima i s drugim modelima

Pionsko-nukleonski član sigma u linearnom sigma modelu

We apply the linear sigma model to analyze pion-nucleon sigma-term. Analytic expresions for these quantities are obtained in terms of the parameters of low-energy physics (pion decay constant and the pion mass). Good results have been obtained in comparison with author\u27s previous work and with other models.Primijenili smo linearni sigma model u analizi pionsko-nukleonskog člana sigma. Analitički izrazi za te veličine izvode se na osnovi parametara nisko-energijske fizike (konstanta raspada i masa piona). Postigli smo dobre ishode u usporedbi s autorovim ranijim radovima i s drugim modelima

A complete characterization of phase space measurements

We characterize all the phase space measurements for a non-relativistic particle.Comment: 11 pages, latex, no figures, iopart styl