17,681 research outputs found
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
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
Pade Interpolation: Methodology and Application to Quarkonium
A novel application of the Pade approximation is proposed in which the Pade
approximant is used as an interpolation for the small and large coupling
behaviors of a physical system, resulting in a prediction of the behavior of
the system at intermediate couplings. This method is applied to quarkonium
systems and reasonable values for the c and b quark masses are obtained.Comment: RevTeX, 12 pages; 1 figure (Figure1.GIF) included at the end; to
appear in the Journal of Mathematical Physic
Gauge Independence and Chiral Symmetry Breaking in a Strong Magnetic Field
The gauge independence of the dynamical fermion mass generated through chiral
symmetry breaking in QED in a strong, constant external magnetic field is
critically examined. We present a (first, to the best of our knowledge)
consistent truncation of the Schwinger-Dyson equations in the lowest Landau
level approximation. We demonstrate that the dynamical fermion mass, obtained
as the solution of the truncated Schwinger-Dyson equations evaluated on the
fermion mass shell, is manifestly gauge independent.Comment: 10 pages, 1 eps figure, version to appear in Annals of Physic
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 and , 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
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