5,225 research outputs found
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
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
Materials review for improved automotive gas turbine engine
The potential role of superalloys, refractory alloys, and ceramics in the hottest sections of engines operating with turbine inlet temperatures as high as 1370 C is examined. The convential superalloys, directionally solidified eutectics, oxide dispersion strenghened alloys, and tungsten fiber reinforced superalloys are reviewed and compared on the basis of maximum turbine blade temperature capability. Improved high temperature protective coatings and special fabrication techniques for these advanced alloys are discussed. Chromium, columbium, molybdenum, tantalum, and tungsten alloys are also reviewed. Molbdenum alloys are found to be the most suitable for mass produced turbine wheels. Various forms and fabrication processes for silicon nitride, silicon carbide, and SIALON's are investigated for use in highstress and medium stress high temperature environments
New Gauge Invariant Formulation of the Chern-Simons Gauge Theory
A new gauge invariant formulation of the relativistic scalar field
interacting with Chern-Simons gauge fields is considered. This formulation is
consistent with the gauge fixed formulation. Furthermore we find that canonical
(Noether) Poincar\'e generators are not gauge invariant even on the constraints
surface and do not satisfy the (classical) Poincar\'e algebra. It is the
improved generators, constructed from the symmetric energy-momentum tensor,
which are (manifestly) gauge invariant and obey the classical Poincar\'e
algebra.Comment: Shortened, to appear as Papid Communication-PRD/Nov/9
Static quark-antiquark potential and Dirac eigenvector correlators
We represent the Polyakov loop correlator as a spectral sum of correlators of
eigenvectors of the lattice Dirac operator. This spectral representation is
studied numerically using quenched SU(3) configurations below and above the
deconfinement temperature. We analyze whether the individual Dirac eigenvector
correlators differ in the confined and deconfined phases. The decay properties
of the normalized Dirac eigenvector correlators turn out to be essentially
identical in the two phases, but the amplitudes change. This change of the
amplitudes shifts the relative contributions of the individual Dirac
eigenvector correlators and is the driving mechanism for the transition from
the confining static potential into the deconfining one
High-temperature liquid-mercury cathodes for ion thrusters Quarterly progress report, 1 Dec. 1966 - 28 Feb. 1967
High temperature liquid mercury cathodes for ion thrusters - thermal design analysi
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
Operator Ordering Problem of the Nonrelativistic Chern-Simons Theory
The operator ordering problem due to the quantization or regularization
ambiguity in the Chern-Simons theory exists. However, we show that this can be
avoided if we require Galilei covariance of the nonrelativistic Abelian
Chern-Simons theory even at the quantum level for the extended sources. The
covariance can be recovered only by choosing some particular operator orderings
for the generators of the Galilei group depending on the quantization
ambiguities of the commutation relation. We show that the
desired ordering for the unusual prescription is not the same as the well-known
normal ordering but still satisfies all the necessary conditions. Furthermore,
we show that the equations of motion can be expressed in a similar form
regardless of the regularization ambiguity. This suggests that the different
regularization prescriptions do not change the physics. On the other hand, for
the case of point sources the regularization prescription is uniquely
determined, and only the orderings, which are equivalent to the usual one, are
allowed.Comment: 18 page
Liquid mercury cathode electron bombardment ion thrusters Summary report, 1 Aug. 1964 - 31 Oct. 1966
Life tests of liquid mercury cathodes for electron bombardment ion thruster
Emulating \emph{ab initio} computations of infinite nucleonic matter
We construct efficient emulators for the \emph{ab initio} computation of the
infinite nuclear matter equation of state. These emulators are based on the
subspace-projected coupled-cluster method for which we here develop a new
algorithm called small-batch voting to eliminate spurious states that might
appear when emulating quantum many-body methods based on a non-Hermitian
Hamiltonian. The efficiency and accuracy of these emulators facilitate a
rigorous statistical analysis within which we explore nuclear matter
predictions for different parametrizations of a chiral interaction
model with explicit -isobars at next-to-next-to leading order.
Constrained by nucleon-nucleon scattering phase shifts and bound-state
observables of light nuclei up to \nuc{4}{He}, we use history matching to
identify non-implausible domains for the low-energy coupling constants of the
chiral interaction. Within these domains we perform a Bayesian analysis using
sampling/importance resampling with different likelihood calibrations and study
correlations between interaction parameters, calibration observables in light
nuclei, and nuclear matter saturation properties.Comment: 16 pages, 15 figures, Supplemental Material provided as ancillary
materia
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