Chiral Symmetry Breaking in an External Field

The effects of an external field on the dynamics of chiral symmetry breaking are studied using quenched, ladder QED as our model gauge field theory. It is found that a uniform external magnetic field enables the chiral symmetry to be spontaneously broken at weak gauge couplings, in contrast with the situation when no external field is present. The broken chiral symmetry is restored at high temperatures as well as at high chemical potentials. The nature of the two chiral phase transitions is different: the transition at high temperatures is a continuous one whereas the phase transition at high chemical potentials is discontinuous.Comment: RevTeX; talk presented at the 2nd Latin American Symposium on High Energy Physics, San Juan, Puerto Rico, April 199

Application of Pad\'{e} interpolation to stationary state problems

If the small and large coupling behavior of a physical system can be computed perturbatively and expressed respectively as power series in a coupling parameter $g$ and $1/g$, a Pad\'{e} approximant embracing the two series can interpolate between these two limits and provide an accurate estimate of the system's behavior in the generally intractable intermediate coupling regime. The methodology and validity of this approach are illustrated by considering several stationary state problems in quantum mechanics.Comment: RevTeX4, 7 pages (including 7 tables); v4 typos correcte

Neutrino Oscillations from String Theory

We derive the character of neutrino oscillations that results from a model of equivalence principle violation suggested recently by Damour and Polyakov as a plausible consequence of string theory. In this model neutrino oscillations will take place through interaction with a long range scalar field of gravitational origin even if the neutrinos are degenerate in mass. The energy dependence of the oscillation length is identical to that in the conventional mass mixing mechanism. This possibility further highlghts the independence of and need for more exacting direct neutrino mass measurements together with a next generation of neutrinoless double beta decay experiments.Comment: 7 pages LaTE