5,046 research outputs found
Dimensional Regularization and Dimensional Reduction in the Light Cone
We calculate all the 2 to 2 scattering process in Yang-Mills theory in the
Light Cone gauge, with the dimensional regulator as the UV regulator. The IR is
regulated with a cutoff in . It supplements our earlier work, where a
Lorentz non-covariant regulator was used and the final results bear some
problems in gauge fixing. Supersymmetry relations among various amplitudes are
checked using the light cone superfields.Comment: current version accepted by PR
A Meta-Analysis of the Effect of Education on Social Capital
To assess the empirical estimates of the effect of education on social trust and social participation - the basic dimensions of individual social capital - a meta-analysis is applied, synthesizing 154 evaluations on social trust, and 286 evaluations on social participation. The publication bias problem is given special emphasis in the meta-analysis. Our statistical synthesis confirms that education is a strong and robust correlate of individual social capital. The meta-analysis provides support for the existence of a relative effect of education on social participation, and of a reciprocity mechanism between the dimensions of social capital. The analysis also suggests that the erosion of social participation during the past decades has coincided with a decrease of the marginal return to education on social capital. Finally, we find differences in the return to education between genders, between US and other nations, and variations for different education attainments.
Higher Education and Membership of Voluntary Groups
This research uses the British National Child Development Study to examine the effect of higher education on individual membership of voluntary groups and organizations. Gender differences in the education effects are given emphasis. We apply parametric and nonparametric econometric methods to isolate the influence of confounding variables. There is strong evidence of education endogeneity in the female sample and we observe a negative education effect on women's group membership. Education endogeneity does not cause serious estimation bias in the male sample. Higher education is a significantly positive determinant of men's group membership. Further investigations from a mid-life perspective reveal that the boost of female participation in the workforce and their attitudes towards employment are key factors in the negative association between higher education and women's group membership. Our research provides clues for the divergence in the enrolment in higher education and social participation behavior in Western countries.
College Education and social trust. An Evidence-based Study on the Causal Mechanisms
This paper examines the influence of college education on social trust at the individual level. Based on the literature of trust and social trust, we hypothesize that life experience/development since adulthood and perceptions of cultural/social structures are two primary channels in the causal linkage between college education and social trust. In the first part of the empirical study econometric techniques are employed to tackle the omitted-variable problem and substantial evidence is found to confirm the positive effect of college education. In the second part contemporary information is used to examine the hypothetical mechanisms in the causal inference. That life experience is a primary channel via which college education promotes social trust fails to find support in our examination, while individual perceptions of cultural and social structures explain up to 77 percent of the causal effect.
Resonant Inelastic X-ray Scattering on Spin-Orbit Coupled Insulating Iridates
We determine how the elementary excitations of iridium-oxide materials, which
are dominated by a strong relativistic spin-orbit coupling, appear in Resonant
Inelastic X-ray Scattering (RIXS). Whereas the RIXS spectral weight at the L2
x-ray edge vanishes, we find it to be strong at the L3-edge. Applying this to
Sr2IrO4, we observe that RIXS, besides being sensitive to local doublet to
quartet transitions, meticulously maps out the strongly dispersive delocalized
excitations of the low-lying spin-orbit doublets.Comment: 4 pages, 3 figure
Electronic Correlations in Oligo-acene and -thiophene Organic Molecular Crystals
From first principles calculations we determine the Coulomb interaction
between two holes on oligo-acene and -thiophene molecules in a crystal, as a
function of the oligomer length. The relaxation of the molecular geometry in
the presence of holes is found to be small. In contrast, the electronic
polarization of the molecules that surround the charged oligomer, reduces the
bare Coulomb repulsion between the holes by approximately a factor of two. In
all cases the effective hole-hole repulsion is much larger than the calculated
valence bandwidth, which implies that at high doping levels the properties of
these organic semiconductors are determined by electron-electron correlations.Comment: 5 pages, 3 figure
Pairing Reentrance Phenomenon in Heated Rotating Nuclei in the Shell Model Monte Carlo Approach
Rotational motion of heated 72-Ge is studied within the microscopic Shell
Model Monte Carlo approach. We investigate the the angular momentum alignment
and nuclear pairing correlations associated with J-pi Cooper pairs as a
function of the rotational frequency and temperature. The reentrance of pairing
correlations with temperature is predicted at high rotational frequencies. It
manifests itself through the anomalous behavior of specific heat and level
density.Comment: 4 pages; 4 figure
On the direct indecomposability of infinite irreducible Coxeter groups and the Isomorphism Problem of Coxeter groups
In this paper we prove, without the finite rank assumption, that any
irreducible Coxeter group of infinite order is directly indecomposable as an
abstract group. The key ingredient of the proof is that we can determine, for
an irreducible Coxeter group, the centralizers of the normal subgroups that are
generated by involutions. As a consequence, we show that the problem of
deciding whether two general Coxeter groups are isomorphic, as abstract groups,
is reduced to the case of irreducible Coxeter groups, without assuming the
finiteness of the number of the irreducible components or their ranks. We also
give a description of the automorphism group of a general Coxeter group in
terms of those of its irreducible components.Comment: 30 page
Dipole Oscillations in Bose - Fermi Mixture in the Time-Dependent Grosspitaevskii and Vlasov equations
We study the dipole collective oscillations in the bose-fermi mixture using a
dynamical time-dependent approach, which are formulated with the time-dependent
Gross-Pitaevskii equation and the Vlasov equation. We find big difference in
behaviors of fermion oscillation between the time-dependent approach and usual
approaches such as the random-phase approximation and the sum-rule approach.
While the bose gas oscillates monotonously, the fermion oscillation shows a
beat and a damping. When the amplitude is not minimal, the dipole oscillation
of the fermi gas cannot be described with a simple center-of-mass motion.Comment: 17 pages text, and 15 figure
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