1,049 research outputs found
The Role of Boundary Conditions in Solving Finite-Energy, Two-Body, Bound-State Bethe-Salpeter Equations
The difficulties that typically prevent numerical solutions from being
obtained to finite-energy, two-body, bound-state Bethe-Salpeter equations can
often be overcome by expanding solutions in terms of basis functions that obey
the boundary conditions. The method discussed here for solving the
Bethe-Salpeter equation requires only that the equation can be Wick rotated and
that the two angular variables associated with rotations in three-dimensional
space can be separated, properties that are possessed by many Bethe-Salpeter
equations including all two-body, bound-state Bethe-Salpeter equations in the
ladder approximation. The efficacy of the method is demonstrated by calculating
finite-energy solutions to the partially-separated Bethe-Salpeter equation
describing the Wick-Cutkosky model when the constituents do not have equal
masses.Comment: 18 page
Off-shell renormalization of the massive QED in the unitary gauge
Despite its simplicity, the unitary gauge is not a popular choice for
practical loop calculations in gauge theories, due to the lack of off-shell
renormalizability. We study the renormalization properties of the off-shell
Green functions of the elementary electron fields in the massive QED, in order
to elucidate the origin and structure of the extra ultraviolet divergences
which exist only in the unitary gauge. We find that all these divergences
affect the Green functions in a trivial way such that in coordinate space the
off-shell Green functions are in fact multiplicatively renormalizable. This
result may generalize to the abelian and non-abelian Higgs theories, for which
the unitary gauge might bring much simplification to the loop calculations.Comment: LaTeX2e, 7 pages, no figure, minor revision in the introductory
paragrap
The application of quantitative methods to the study of early development and ovarian structure in mammals
Introduction â˘
I The Pluriovular Follicle, with Reference to its
Occurrence in the Ferret â˘
II The Technique of Estimating Small Irregular Areas
in Biological Research, with Notes on the Tests
of Accuracy â˘
III The Early Development of the Ferret: the Pronuclei â˘
IV The Measurement of Ferret Pronuclei â˘
V The Sizes of Ferret Pronuclei â˘
VI A Quantitative Study of the Polar Body of the Ferret,
with a Note on the Second Polar Spindle â˘
VII The Early Development of the Ferret: the Cytoplasm â˘
VIII The Early Development of the Ferret: the Zona
Granulosa, Zona Pellucida and Associated Structures â˘
IX The Volumes of Ferret Ova, with Special Reference
to the Methods of Determination â˘
X A Study of the Sizes of Nuclei in Ovarian Stroma â˘
Appendix -- Posterior Duplicity in a Dog, with â˘
Reference to Mammalian Teratology in Genera
Political Instability in Developing Areas
Seen in broad sociological terms, the impact of economically and technologically advanced societies has disrupted every aspect of the developing world\u27s traditional societies and has touched off the complex processes of modernization and development
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