112 research outputs found
Self-Interaction and Gauge Invariance
A simple unified closed form derivation of the non-linearities of the
Einstein, Yang-Mills and spinless (e.g., chiral) meson systems is given. For
the first two, the non-linearities are required by locality and consistency; in
all cases, they are determined by the conserved currents associated with the
initial (linear) gauge invariance of the first kind. Use of first-order
formalism leads uniformly to a simple cubic self-interaction.Comment: Missing last reference added. 9 pages, This article, the first paper
in Gen. Rel. Grav. [1 (1970) 9], is now somewhat inaccessible; the present
posting is the original version, with a few subsequent references included.
Updates update
Unification of the Soluble Two-dimensional vector coupling models
The general theory of a massless fermion coupled to a massive vector meson in
two dimensions is formulated and solved to obtain the complete set of Green's
functions. Both vector and axial vector couplings are included. In addition to
the boson mass and the two coupling constants, a coefficient which denotes a
particular current definition is required for a unique specification of the
model.
The resulting four parameter theory and its solution are shown to reduce in
appropriate limits to all the known soluble models, including in particular the
Schwinger model and its axial vector variant.Comment: 10 page
Soluble field theory with a massless gauge invariant limit
It is shown that there exists a soluble four parameter model in (1+1)
dimensions all of whose propagators can be determined in terms of the
corresponding known propagators of the vector coupling theory. Unlike the
latter case, however, the limit of zero bare mass is nonsingular and yields a
nontrivial theory with a rigorously unbroken gauge invariance.Comment: 7 pages, revtex, no figure
Reconsidered estimates of the 10th order QED contributions to the muon anomaly
The problem of estimating the 10th order QED corrections to the muon
anomalous magnetic moment is reconsidered. The incorporation of the recently
improved contributions to the and - corrections to
within the renormalization-group inspired scheme-invariant approach
leads to the estimate . It is in good
agreement with the estimate , obtained
by Kinoshita and Nio from the numerical calculations of 2958 10-th order
diagrams, which are considered to be more important than the still uncalculated
6122 10th-order -dependent vertex graphs, and 12672 5-loop
diagrams, responsible for the mass-independent constant contribution both to
and . This confirms Kinoshita and Nio guess about dominance of
the 10-th order diagrams calculated by them. Comparisons with other estimates
of the - contributions to , which exist in the literature,
are presented.Comment: 19 pages, LaTeX, some misprints in the text and literature corrected.
Results unchaged, to appear in Phys.Rev.
Supersymmetry and the Chiral Schwinger Model
We have constructed the N=1/2 supersymmetric general Abelian model with
asymmetric chiral couplings. This leads to a N=1/2 supersymmetrization of the
Schwinger model. We show that the supersymmetric general model is plagued with
problems of infrared divergence. Only the supersymmetric chiral Schwinger model
is free from such problems and is dynamically equivalent to the chiral
Schwinger model because of the peculiar structure of the N=1/2 multiplets.Comment: one 9 pages Latex file, one ps file with one figur
Quantum Electrodynamics of the Helium Atom
Using singlet S states of the helium atom as an example, I describe precise
calculation of energy levels in few-electron atoms. In particular, a complete
set of effective operators is derived which generates O(m*alpha^6) relativistic
and radiative corrections to the Schr"odinger energy. Average values of these
operators can be calculated using a variational Schr"odinger wave function.Comment: 23 pages, revte
Vector mesons in a relativistic point-form approach
We apply the point form of relativistic quantum mechanics to develop a
Poincare invariant coupled-channel formalism for two-particle systems
interacting via one-particle exchange. This approach takes the exchange
particle explicitly into account and leads to a generalized eigenvalue equation
for the Bakamjian-Thomas type mass operator of the system. The coupling of the
exchange particle is derived from quantum field theory. As an illustrative
example we consider vector mesons within the chiral constituent quark model in
which the hyperfine interaction between the confined quark-antiquark pair is
generated by Goldstone-boson exchange. We study the effect of retardation in
the Goldstone-boson exchange by comparing with the commonly used instantaneous
approximation. As a nice physical feature we find that the problem of a too
large - splitting can nearly be avoided by taking the dynamics of
the exchange meson explicitly into account.Comment: 14 pages, 1 figur
Exact Effective Action for (1+1 Dimensional) Fermions in an Abelian Background at Finite Temperature
In an effort to further understand the structure of effective actions for
fermions in an external gauge background at finite temperature, we study the
example of 1+1 dimensional fermions interacting with an arbitrary Abelian gauge
field. We evaluate the effective action exactly at finite temperature. This
effective action is non-analytic as is expected at finite temperature. However,
contrary to the structure at zero temperature and contrary to naive
expectations, the effective action at finite temperature has interactions to
all (even) orders (which, however, do not lead to any quantum corrections). The
covariant structure thus obtained may prove useful in studying 2+1 dimensional
models in arbitrary backgrounds. We also comment briefly on the solubility of
various 1+1 dimensional models at finite temperature.Comment: A few clarifying remarks added;21 page
Particle Spectrum Created Through Bubble Nucleation
Using the multi-dimensional wave function formalism, we investigate the
quantum state of a scalar field inside a true vacuum bubble nucleated through
false vacuum decay in flat spacetime. We developed a formalism which allows us
a mode-by-mode analysis. To demonstrate its advantage, we describe in detail
the evolution of the quantum state during the tunneling process in terms of
individual mode functions and interpret the result in the language of particle
creation. The spectrum of the created particles is examined based on quantum
field theory in the Milne universe.Comment: 14 pages, revtex file, 4 uuencoded compressed postscript figures
appended at the en
Hadronic Loop Corrections to the Muon Anomalous Magnetic Moment
The dominant theoretical uncertainties in both, the anomalous magnetic moment
of the muon and the value of the electromagnetic coupling at the Z scale arise
from their hadronic contributions. Since these will ultimately dominate the
experimental errors, we study the correlation between them, as well as with
other fundamental parameters. To this end we present analytical formulas for
the QCD contribution from higher energies and from heavy quarks. Including
these correlations affects the Higgs boson mass extracted from precision data.Comment: 4 page
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