1,344 research outputs found
Operator product expansion of the energy momentum tensor in 2D conformal field theories on manifolds with boundary
Starting from the well-known expression for the trace anomaly we derive the
operator product expansion of the energy-momentum tensor in 2D
conformal theories defined in the upper halfplane making use of the
additional condition of no energy-momentum flux across the boundary. The OPE
turns out to be the same as in the absence of the boundary. For this result it
is crucial that the trace anomaly is proportional to the Gau\ss-Bonnet density.
Some relations to the - model approach for open strings are discussed.Comment: 8 pages, Latex, HU Berlin-IEP-93/
Marginalization using the metric of the likelihood
Although the likelihood function is normalizeable with respect to the data
there is no guarantee that the same holds with respect to the model parameters.
This may lead to singularities in the expectation value integral of these
parameters, especially if the prior information is not sufficient to take care
of finite integral values. However, the problem may be solved by obeying the
correct Riemannian metric imposed by the likelihood. This will be demonstrated
for the example of the electron temperature evaluation in hydrogen plasmas.Comment: 8 pages, 2 figures, Presented at the MaxEnt 2000 conference in
Gif-sur-Yvette/Pari
Bayesian analysis of magnetic island dynamics
We examine a first order differential equation with respect to time coming up
in the description of magnetic islands in magnetically confined plasmas. The
free parameters of this equation are obtained by employing Bayesian probability
theory. Additionally a typical Bayesian change point is solved in the process
of obtaining the data.Comment: 10 pages, 4 figures, submitted to be included in MaxEnt 2002
proceeding
The local dust foregrounds in the microwave sky: I. Thermal emission spectra
Analyses of the cosmic microwave background (CMB) radiation maps made by the
Wilkinson Microwave Anisotropy Probe (WMAP) have revealed anomalies not
predicted by the standard inflationary cosmology. In particular, the power of
the quadrupole moment of the CMB fluctuations is remarkably low, and the
quadrupole and octopole moments are aligned mutually and with the geometry of
the Solar system. It has been suggested in the literature that microwave sky
pollution by an unidentified dust cloud in the vicinity of the Solar system may
be the cause for these anomalies. In this paper, we simulate the thermal
emission by clouds of spherical homogeneous particles of several materials.
Spectral constraints from the WMAP multi-wavelength data and earlier infrared
observations on the hypothetical dust cloud are used to determine the dust
cloud's physical characteristics. In order for its emissivity to demonstrate a
flat, CMB-like wavelength dependence over the WMAP wavelengths (3 through 14
mm), and to be invisible in the infrared light, its particles must be
macroscopic. Silicate spheres from several millimetres in size and carbonaceous
particles an order of magnitude smaller will suffice. According to our
estimates of the abundance of such particles in the Zodiacal cloud and
trans-neptunian belt, yielding the optical depths of the order of 1E-7 for each
cloud, the Solar-system dust can well contribute 10 microKelvin (within an
order of magnitude) in the microwaves. This is not only intriguingly close to
the magnitude of the anomalies (about 30 microKelvin), but also alarmingly
above the presently believed magnitude of systematic biases of the WMAP results
(below 5 microKelvin) and, to an even greater degree, of the future missions
with higher sensitivities, e.g. PLANCK.Comment: 33 pages, 9 figures, 1 table. The Astrophysical Journal, 2009,
accepte
Decomposition of multicomponent mass spectra using Bayesian probability theory
We present a method for the decomposition of mass spectra of mixture gases
using Bayesian probability theory. The method works without any calibration
measurement and therefore applies also to the analysis of spectra containing
unstable species. For the example of mixtures of three different hydrocarbon
gases the algorithm provides concentrations and cracking coefficients of each
mixture component as well as their confidence intervals. The amount of
information needed to obtain reliable results and its relation to the accuracy
of our analysis are discussed
Pseudopotential Approaches to Ca, Sr and Ba Hybrides. Why are some Alkaline Earth MX Compounds Bent?
Quasirelativistic and nonrelativistic lo-valence-electronp seudopotentialsf or Ca, Sr, and Ba are presented. Results of calculations with 6s6p5d basis sets for MH, MH , and MH, are compared with all-electron and 2-valence-electron pseudopotential calculations with and , without core-polarization potentials. The lo-valence-electron pseudopotential approach agrees well with all-electron calculations. It circumvents problems for the 2-valence-electron pseudopotentials arising from an incomplete separation of valence and subvalence shells in polar molecular systems due to strongly contracted occupied (n - 1 )-d orbitals. All higherlevel calculations show SrH and BaII, to be bent with angles of - 140° and 120°, respectively, while CaH is linear with a flat potential-energy surface for the bending motion. The use of a core-polarization potential together with the 2-valence-electronp seudopotentiala pproach allows an investigation of the relative importance of core-polarization vs direct d-orbital bonding participation as reasons for the bent structures. The calculations strongly suggest that both contribute to the bending in SrH and BaII. Even at the Hartree-Fock level of theory lovalence- electronp seudopotentialc alculations given reasonablea nglesw hen the potentialenergy surface is not exceedingly flat, and only moderately contracted basis sets including both compact d functions and diffuse p functions are used. The effect of core-valence correlation and the importance off functions also are discussed
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Towards a conceptual definition of intangible Olympic legacy
Copyright © 2021, Vassil Girginov and Holger Preuss. Purpose
Intangible legacy encapsulates the essence of Olympism and its manifestation, the Olympic Games. Despite significant interest in the capacity of the Olympics to produce notable changes in society, conceptual difficulties in defining and measuring intangible legacy persist. The study develops a conceptual definition of intangible Olympic legacy.
Design/methodology/approach
The study follows a four-step concept definition approach. It examines and integrates three strands of literature including intangibles, social interactions and public value, which is combined with insights from a longitudinal empirical investigation of intangible Olympic legacy for National Sport Organisations (NSO).
Findings
The proposed concept of intangible legacy defines it an emerging combination of attributes, interactions, processes and technology, with the goal of creating public value which is the ultimate goal of the Olympic Games. Since intangible legacy is qualitative rather than quantitative, a reconsideration of the current research paradigm is also proposed.
Research limitations/implications
The study develops a new analytical device for the investigation of intangible legacies for specific publics such as NSO.
Practical implications
The study carries practical implications for Olympic and events/festival promoters as it allows defining and operationalising the key attributes of the concept.
Originality/value
This is the first study to conceptualise intangible legacy of mega events.International Olympic Committee (Olympic Studies Centre)
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