1,045 research outputs found
Growth of Hg1−xCdxTe single crystals by travelling heater method under accelerated crucible rotation conditions
The accelerated crucible rotation technique (ACRT) has been applied to the THM growth of Hg1−xCdxTe crystals to grow the crystals at a higher rate. These higher growth rates, which should be achieved by extending the regions of conventional stirring towards the interfaces, have been used in an attempt to explain the results in terms of simple constitutional supercooling arguments. Some different ACRT cycles which fulfil simple hydrodynamic and geometric criteria have been studied. The grown crystals were investigated with respect to their metallurgical homogeneity and their structural perfection. These properties have not been degraded by increasing the growth rate from 1.5 to 8.5 mm per day
Gauge Consistent Wilson Renormalization Group II: Non-Abelian Case
We give a wilsonian formulation of non-abelian gauge theories explicitly
consistent with axial gauge Ward identitities. The issues of unitarity and
dependence on the quantization direction are carefully investigated. A
wilsonian computation of the one-loop QCD beta function is performed.Comment: 34 pages, 1 eps figure, latex2e. Minor changes, version to appear in
Int. J. Mod. Phy
The Fermion Self-Energy during Inflation
We compute the one loop fermion self-energy for massless Dirac + Einstein in
the presence of a locally de Sitter background. We employ dimensional
regularization and obtain a fully renormalized result by absorbing all
divergences with BPHZ counterterms. An interesting technical aspect of this
computation is the need for a noninvariant counterterm owing to the breaking of
de Sitter invariance by our gauge condition. Our result can be used in the
quantum-corrected Dirac equation to search for inflation-enhanced quantum
effects from gravitons, analogous to those which have been found for massless,
minimally coupled scalars.Comment: 63 pages, 3 figures (uses axodraw.sty), LaTeX 2epsilon. Revised
version (to appear in Classical and Quantum Gravity) corrects some typoes and
contains some new reference
Supersymmetric Yang-Mills-Chern-Simons theory
We prove that three-dimensional N=1 supersymmetric Yang-Mills-Chern-Simons
theory is finite to all loops. This leaves open the possibility that different
regularization methods give different finite effective actions. We show that
for this model dimensional regularization and regularization by dimensional
reduction yield the same effective action.Comment: 6 pages, 1 figure, latex, espcrc2. Contribution to the Proceedings of
the 30th Ahrenshoop Symposium on the Theory of Elementary Particles, edited
by D. Lust, H.-J. Otto and G. Weigt, to appear in Nuclear Physics B,
Proceedings Supplemen
Decoupling of the -scalar mass in softly broken supersymmetry
It has been shown recently that the introduction of an unphysical
-scalar mass is necessary for the proper renormalization
of softly broken supersymmetric theories by dimensional reduction (\drbar).
In these theories, both the two-loop -functions of the scalar masses and
their one-loop finite corrections depend on . We find, however,
that the dependence on can be completely removed by slightly
modifying the \drbar renormalization scheme. We also show that previous \drbar
calculations of one-loop corrections in supersymmetry which ignored the
contribution correspond to using this modified scheme.Comment: 7 pages, LTH-336, NUB-3094-94TH, KEK-TH-40
Regularization Dependence of Running Couplings in Softly Broken Supersymmetry
We discuss the dependence of running couplings on the choice of
regularization method in a general softly-broken N=1 supersymmetric theory.
Regularization by dimensional reduction respects supersymmetry, but standard
dimensional regularization does not. We find expressions for the differences
between running couplings in the modified minimal subtraction schemes of these
two regularization methods, to one loop order. We also find the two-loop
renormalization group equations for gaugino masses in both schemes, and discuss
the application of these results to the Minimal Supersymmetric Standard Model.Comment: 11 pages. v2: Signs of equations (1.2) and (4.2) are fixe
Two-loop renormalization of gaugino masses in general supersymmetric gauge models
We calculate the two-loop renormalization group equations for the running
gaugino masses in general SUSY gauge models, improving our previous result. We
also study its consequence to the unification of the gaugino masses in the SUSY
SU(5) model. The two-loop correction to the one-loop relation
is found to be of the order of a few \%.Comment: 8 pages + 1 figure (omitted),KEK-TH-371 / UT-65
Trace Anomaly and Backreaction of the Dynamical Casimir Effect
The Casimir energy for massless scalar field which satisfies priodic boundary
conditions in two-dimensional domain wall background is calculated by making
use of general properties of renormalized stress-tensor. The line element of
domain wall is time dependent, the trace anomaly which is the nonvanishing
for a conformally invariant field after renormalization,
represent the back reaction of the dynamical Casimir effect.Comment: 8 pages, no figures, typos corrected, discussion added, has been
accepted for the publication in GR
Relation between the pole and the minimally subtracted mass in dimensional regularization and dimensional reduction to three-loop order
We compute the relation between the pole quark mass and the minimally
subtracted quark mass in the framework of QCD applying dimensional reduction as
a regularization scheme. Special emphasis is put on the evanescent couplings
and the renormalization of the epsilon-scalar mass. As a by-product we obtain
the three-loop on-shell renormalization constants Zm(OS) and Z2(OS) in
dimensional regularization and thus provide the first independent check of the
analytical results computed several years ago.Comment: 22 page
General structure of the graviton self-energy
The graviton self-energy at finite temperature depends on fourteen structure
functions. We show that, in the absence of tadpoles, the gauge invariance of
the effective action imposes three non-linear relations among these functions.
The consequences of such constraints, which must be satisfied by the thermal
graviton self-energy to all orders, are explicitly verified in general linear
gauges to one loop order.Comment: 4 pages, minor corrections of typo
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