15,512 research outputs found
One-loop N-point equivalence among negative-dimensional, Mellin-Barnes and Feynman parametrization approaches to Feynman integrals
We show that at one-loop order, negative-dimensional, Mellin-Barnes' (MB) and
Feynman parametrization (FP) approaches to Feynman loop integrals calculations
are equivalent. Starting with a generating functional, for two and then for
-point scalar integrals we show how to reobtain MB results, using
negative-dimensional and FP techniques. The point result is valid for
different masses, arbitrary exponents of propagators and dimension.Comment: 11 pages, LaTeX. To be published in J.Phys.
General massive one-loop off-shell three-point functions
In this work we compute the most general massive one-loop off-shell
three-point vertex in D-dimensions, where the masses, external momenta, and
exponents of propagators are arbitrary. This follows our previous paper in
which we have calculated several new hypergeometric series representations for
massless and massive (with equal masses) scalar one-loop three-point functions,
in the negative dimensional approach.Comment: 16 pages, 2 figures, 4 table
Cosmic strings in axionic-dilatonic gravity
We first consider local cosmic strings in dilaton-axion gravity and show that
they are singular solutions. Then we take a supermassive Higgs limit and
present expressions for the fields at far distances from the core by applying a
Pecci-Quinn and a duality transformation to the dilatonic Melvin's magnetic
universe.Comment: Latex file. 16 page
Exploiting Term Hiding to Reduce Run-time Checking Overhead
One of the most attractive features of untyped languages is the flexibility
in term creation and manipulation. However, with such power comes the
responsibility of ensuring the correctness of these operations. A solution is
adding run-time checks to the program via assertions, but this can introduce
overheads that are in many cases impractical. While static analysis can greatly
reduce such overheads, the gains depend strongly on the quality of the
information inferred. Reusable libraries, i.e., library modules that are
pre-compiled independently of the client, pose special challenges in this
context. We propose a technique which takes advantage of module systems which
can hide a selected set of functor symbols to significantly enrich the shape
information that can be inferred for reusable libraries, as well as an improved
run-time checking approach that leverages the proposed mechanisms to achieve
large reductions in overhead, closer to those of static languages, even in the
reusable-library context. While the approach is general and system-independent,
we present it for concreteness in the context of the Ciao assertion language
and combined static/dynamic checking framework. Our method maintains the full
expressiveness of the assertion language in this context. In contrast to other
approaches it does not introduce the need to switch the language to a (static)
type system, which is known to change the semantics in languages like Prolog.
We also study the approach experimentally and evaluate the overhead reduction
achieved in the run-time checks.Comment: 26 pages, 10 figures, 2 tables; an extension of the paper version
accepted to PADL'18 (includes proofs, extra figures and examples omitted due
to space reasons
Exactly solvable models for triatomic-molecular Bose-Einstein Condensates
We construct a family of triatomic models for heteronuclear and homonuclear
molecular Bose-Einstein condensates. We show that these new generalized models
are exactly solvable through the algebraic Bethe ansatz method and derive their
corresponding Bethe ansatz equations and energies.Comment: 11 page
Natural Diagonal Riemannian Almost Product and Para-Hermitian Cotangent Bundles
We obtain the natural diagonal almost product and locally product structures
on the total space of the cotangent bundle of a Riemannian manifold. We find
the Riemannian almost product (locally product) and the (almost) para-Hermitian
cotangent bundles of natural diagonal lift type. We prove the characterization
theorem for the natural diagonal (almost) para-K\"ahlerian structures on the
total spaces of the cotangent bundle.Comment: 10 pages, will appear in Czechoslovak Mathematical Journa
Effects of hCG on progesterone concentrations and fertility in cyclic, lactating Alpine goats.
The objective of this study was to evaluate the effect of hCG administration on plasma progesterone concentrations in lactating Alpine goats during the natural breeding season. After detection of estrus, 124 does were randomly assigned to one of two treatments (T1 and T2). In T1 (n = 60) and T2 (n = 64), the animals received 1 ml of saline solution or 250 IU of hCG i.m., respectively, 5 days after the first detection of estrus and breeding. Plasma progesterone concentration (ng/mL) was determined from blood sampled (T1 = 12 and T2 = 13) on Days 0 (day of estrus), 5, 7, 13, 17, 21, 28 and 45 after breeding. Two control goats with short cycles and two nymphomaniac goats (one per treatment) were detected. Plasma progesterone concentration (mean ± SEM) for T1 and T2 females differed on Days 13, 17 (P 0.05) between T1 (78.3%) and T2 (84.4%) does. The hCG administration 5 days after breeding increased plasma progesterone concentrations on Days 13 to 21 but did not increase pregnancy rate
Impurity Effects on Superconductivity on Surfaces of Topological Insulators
A two-dimensional superconductor (SC) on surfaces of topological insulators
(TIs) is a mixture of s-wave and helical p-wave components when induced by
s-wave interactions, since spin and momentum are correlated. On the basis of
the Abrikosov-Gor'kov theory, we reveal that unconventional SCs on the surfaces
of TIs are stable against time-reversal symmetric (TRS) impurities within a
region of small impurity concentration. Moreover, we analyze the stability of
the SC on the surfaces of TIs against impurities beyond the perturbation theory
by solving the real-space Bogoliubov-de Gennes equation for an effective
tight-binding model of a TI. We find that the SC is stable against strong TRS
impurities. The behaviors of bound states around an impurity suggest that the
SC on the surfaces of TIs is not a topological SC.Comment: 17 pages, 14 figures, to appear in J. Phys. Soc. Jp
Plasmons in layered structures including graphene
We investigate the optical properties of layered structures with graphene at
the interface for arbitrary linear polarization at finite temperature including
full retardation by working in the Weyl gauge. As a special case, we obtain the
full response and the related dielectric function of a layered structure with
two interfaces. We apply our results to discuss the longitudinal plasmon
spectrum of several single and double layer devices such as systems with finite
and zero electronic densities. We further show that a nonhomogeneous dielectric
background can shift the relative weight of the in-phase and out-of-phase mode
and discuss how the plasmonic mode of the upper layer can be tuned into an
acoustic mode with specific sound velocity.Comment: 18 pages, 6 figure
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