8,014 research outputs found
Equivalences of Smooth and Continuous Principal Bundles with Infinite-Dimensional Structure Group
Let K be a a Lie group, modeled on a locally convex space, and M a
finite-dimensional paracompact manifold with corners. We show that each
continuous principal K-bundle over M is continuously equivalent to a smooth one
and that two smooth principal K-bundles over M which are continuously
equivalent are also smoothly equivalent. In the concluding section, we relate
our results to neighboring topics.Comment: 18 pages, final versio
Robust a priori and a posteriori error analysis for the approximation of Allen–Cahn and Ginzburg–Landau equations past topological changes
A priori and a posteriori error estimates are derived for the numerical approximation of scalar and complex valued phase field models. Particular attention is devoted to the dependence of the estimates on a small parameter and to the validity of the estimates in the presence of topological changes in the solution that represents singular points in the evolution. For typical singularities the estimates depend on the inverse of the parameter in a polynomial as opposed to exponential dependence of estimates resulting from a straightforward error analysis. The estimates naturally lead to adaptive mesh refinement and coarsening algorithms. Numerical experiments illustrate the reliability and efficiency of this approach for the evolution of interfaces and vortices that undergo topological changes
Transitions in Two-Higgs-Doublet Models
In this article we study transitions and possible
correlations with the anomalous magnetic moment of the muon () within
two-Higgs-doublet models with generic Yukawa couplings, including the
possibility of right-handed neutrinos. We perform the matching on the relevant
effective Hamiltonian and calculate the leading one-loop effects for , , , and transitions in a general
gauge. Concerning the phenomenology, we find that an explanation of the hints
for new physics in data is possible once right-handed
neutrinos are included. If lepton flavour violating couplings are allowed, one
can account for the discrepancy in as well. However, only a small
portion of parameter space gives a good fit to data and the
current bound on requires the mixing between the neutral Higgses
to be very small if one aims at an explanation of .Comment: 40 pages, 1 table, 10 figure
Price adjustment to news with uncertain precision
Bayesian learning provides the core concept of processing noisy information. In standard Bayesian frameworks, assessing the price impact of information requires perfect knowledge of news’ precision. In practice, however, precision is rarely dis- closed. Therefore, we extend standard Bayesian learning, suggesting traders infer news’ precision from magnitudes of surprises and from external sources. We show that interactions of the different precision signals may result in highly nonlinear price responses. Empirical tests based on intra-day T-bond futures price reactions to employment releases confirm the model’s predictions and show that the effects are statistically and economically significant
Temperature Independent Renormalization of Finite Temperature Field Theory
We analyse 4-dimensional massive \vp^4 theory at finite temperature T in
the imaginary-time formalism. We present a rigorous proof that this quantum
field theory is renormalizable, to all orders of the loop expansion. Our main
point is to show that the counterterms can be chosen temperature independent,
so that the temperature flow of the relevant parameters as a function of
can be followed. Our result confirms the experience from explicit calculations
to the leading orders. The proof is based on flow equations, i.e. on the
(perturbative) Wilson renormalization group. In fact we will show that the
difference between the theories at T>0 and at T=0 contains no relevant terms.
Contrary to BPHZ type formalisms our approach permits to lay hand on
renormalization conditions and counterterms at the same time, since both appear
as boundary terms of the renormalization group flow. This is crucial for the
proof.Comment: 17 pages, typos and one footnote added, to appear in Ann.H.Poincar
Economic impacts of a premature nuclear phase-out in Switzerland
This paper investigates the economic impacts of two policy proposals: "Strom ohne Atom" (SOA) and "Moratorium Plus" (MOP), both of which contain a premature phase-out of nuclear power in Switzerland. While MOP restricts business-as-usual operation time of existing nuclear power plants to 40 years, which results in a cutback of 10-20 years, SOA foresees a reduction in operation time of 20-30 years and administers combined heat and power to substitute for nuclear energy. Based on simulations with an intertemporal multi-sector general equilibrium model of the Swiss economy, we quantify the price tags for risk reduction from nuclear power operation given additional constraints on back-up technologies. Costs of accelerating the phase-out of nuclear power for an average household amount to 200 CHF/a over the next 45 years under SOA and drop to 60 CHF/a in the case of MOP. If Switzerland were to assure carbon neutrality of a premature phase-out by the use of carbon taxes, adjustment costs would increase to 230 CHF under SOA and 110 CHF under MOP. --nuclear phase-out,computable general equilibrium
A fiscal outlook for Poland using generational accounts
During the next few decades the populations of most developed countries will grow older and older as a result of the low fertility rates since the 1970s and/or the continuously increasing life expectancy. Poland, one of the biggest countries in Central Europe, will be confronted rather seriously by this development. Generational Accounting which was introduced in the early nineties, can illustrate the effects of this ageing process on a country's fiscal situation. We show that the demographic development produces a major problem for the long term stability of Polish public finances. In particular the healthcare system deserves special attention for policy makers in the medium and long run, whilst the general pension system shall stabilise in the long term. --Generational Accounting,Fiscal sustainability,Fiscal policy,Poland,Pension reform
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