27 research outputs found
Spectral density in resonance region and analytic confinement
We study the role of finite widths of resonances in a nonlocal version of the
Wick-Cutkosky model. The spectrum of bound states is known analytically in this
model and forms linear Regge tragectories. We compute the widths of resonances,
calculate the spectral density in an extension of the Breit-Wigner {\it ansatz}
and discuss a mechanism for the damping of unphysical exponential growth of
observables at high energy due to finite widths of resonances.Comment: 13 pages, RevTeX, 6 figures. Revised version with typographical
corrections and additional comments in conclusion
On Locality in Quantum General Relativity and Quantum Gravity
The physical concept of locality is first analyzed in the special
relativistic quantum regime, and compared with that of microcausality and the
local commutativity of quantum fields. Its extrapolation to quantum general
relativity on quantum bundles over curved spacetime is then described. It is
shown that the resulting formulation of quantum-geometric locality based on the
concept of local quantum frame incorporating a fundamental length embodies the
key geometric and topological aspects of this concept. Taken in conjunction
with the strong equivalence principle and the path-integral formulation of
quantum propagation, quantum-geometric locality leads in a natural manner to
the formulation of quantum-geometric propagation in curved spacetime. Its
extrapolation to geometric quantum gravity formulated over quantum spacetime is
described and analyzed.Comment: Mac-Word file translated to postscript for submission. The author may
be reached at: [email protected] To appear in Found. Phys. vol. 27,
199