Study of the Leutwyler-Smilga regimes: Lessons for full QCD simulations

Some key points out of my recent study of the characteristic features of the small ($x \ll 1$), intermediate ($x \simeq 1$) and large ($x \gg 1$) Leutwyler-Smilga regimes for QCD-type theories in a finite volume ($x = V \Sigma m$) are presented, and a few immediate consequences for full QCD simulations are discussed.Comment: Lattice 2000 (Topology and Confinement), 4 pages, 4 figures comprising 16 plots: cosmetic change

Current algebra derivation of temperature dependence of hadron couplings with currents

The vector and the axial-vector meson couplings with the vector and the axial-vector currents respectively at finite temperature have been obtained in Ref. \cite{Mallik} by calculating all the relevant one-loop Feynman graphs with vertices obtained from the effective chiral Lagrangian. On the other hand, the same couplings were also derived in Ref.\cite{Ioffe1} by applying the method of current algebra and the hypothesis of partial conservation of axial-vector current (PCAC). The latter method appears to miss certain terms; in the case of the vector meson coupling with the vector current, for example, a term containing the $\rho\omega\pi$ coupling is missed. A similar situation would also appear for the nucleon coupling with the nucleon current. In this note we resolve these differences.Comment: 7 pages, 2 eps figure

Lattice QCD data versus Chiral Perturbation Theory: the case of MπM_\pi

I present a selection of recent lattice data by major collaborations for the pseudo-Goldstone boson masses in full ($N_f=2$) QCD, where the valence quarks are chosen exactly degenerate with the sea quarks. At least the more chiral points should be consistent with Chiral Perturbation Theory for the latter to be useful in extrapolating to physical masses. Perspectives to reliably determine NLO Gasser-Leutwyler coefficients are discussed.Comment: 3 pages, 4 figures, ICHEP 2002, v2: one statement clarified, one ref. adde

Strong Interactions at Low Energy

The lectures review some of the basic concepts relevant for an understanding of the low energy properties of the strong interactions: chiral symmetry, spontaneous symmetry breakdown, Goldstone bosons, quark condensate. The effective field theory used to analyze the low energy structure is briefly sketched. As an illustration, I discuss the implications of the recent data on the decay $K\to \pi\pi e\nu$ for the magnitude of the quark condensate.Comment: Lectures given at the school of physics "Understanding the structure of hadrons", Prague, July 2001, 20 p

Chiral Perturbation Theory for the Quenched Approximation of QCD

[This version is a minor revision of a previously submitted preprint. Only references have been changed.] We describe a technique for constructing the effective chiral theory for quenched QCD. The effective theory which results is a lagrangian one, with a graded symmetry group which mixes Goldstone bosons and fermions, and with a definite (though slightly peculiar) set of Feynman rules. The straightforward application of these rules gives automatic cancellation of diagrams which would arise from virtual quark loops. The techniques are used to calculate chiral logarithms in $f_K/f_\pi$, $m_\pi$, $m_K$, and the ratio of $\langle{\bar s}s\rangle$ to $\langle{\bar u}u\rangle$. The leading finite-volume corrections to these quantities are also computed. Problems for future study are described.Comment: 14 page

Holography with Gravitational Chern-Simons Term

The holographic description in the presence of gravitational Chern-Simons term is studied. The modified gravitational equations are integrated by using the Fefferman-Graham expansion and the holographic stress-energy tensor is identified. The stress-energy tensor has both conformal anomaly and gravitational or, if re-formulated in terms of the zweibein, Lorentz anomaly. We comment on the structure of anomalies in two dimensions and show that the two-dimensional stress-energy tensor can be reproduced by integrating the conformal and gravitational anomalies. We study the black hole entropy in theories with a gravitational Chern-Simons term and find that the usual Bekenstein-Hawking entropy is modified. For the BTZ black hole the modification is determined by area of the inner horizon. We show that the total entropy of the BTZ black hole is precisely reproduced in a boundary CFT calculation using the Cardy formula.Comment: 19 pages, Latex; v3: minor corrections, some clarification

Topology and pion correlators -- a study in the N_f=2 Schwinger model

I readdress the issue whether the topological charge of the gauge background has an influence on a hadronic observable. To this end pion correlators in the Schwinger model with 2 dynamical flavours are determined on subensembles with a fixed topological charge. It turns out that the answer depends on a specific function of the sea-quark mass and the box volume which is in close analogy to the Leutwyler-Smilga parameter in full QCD.Comment: Lattice2001(confinement), 3 pages, 2 figure

Aspects of quark mass generation on a torus

In this talk we report on recent results for the quark propagator on a compact manifold. The corresponding Dyson-Schwinger equations on a torus are solved on volumes similar to the ones used in lattice calculations. The quark-gluon interaction is fixed such that the lattice results are reproduced. We discuss both the effects in the infinite volume/continuum limit as well as effects when the volume is small.Comment: 3 pages, 3 figures; talk given by CF at QNP06, Madrid, June 200

The structure of teacher-specific intercultural competence: Empirical evidence on the 'Beliefs, Values, and Goals' dimension

The aim of this contribution is to identify the elements that are integral parts of a teacher-specific intercultural competence construct. In this paper, we focus on those facets of the construct that are considered to be rather value-laden and affectively tinged. Following the widely used theoretical model of teachers’ professional competencies developed by Baumert and Kunter (2013), we conceptually place these facets within the Beliefs, Values, & Goals dimension, and propose four core elements: (1) appreciation of cultural diversity; (2) ethno-relative worldview; (3) attitudes toward integration; and (4) identification with goals of intercultural education. In order to test the hypothesis that these four aspects represent one single overarching latent construct, we operationalized each with an appropriate scale and then scrutinized the instruments’ internal consistency, and convergent and factorial validity. The results suggest that our four scales have good internal consistencies (Cronbach’s alphas between .82 and .89), adhere to a one-factor structure (as demonstrated by Confirmatory Factor Analysis), and indicate one latent construct (RMSEA = 0.000; TLI = 1.004; CFI = 1.000; SRMR = .007). With these results, this paper presents a valid, contextually relevant new instrument to assess (pre-service) teachers’ beliefs, values and goals regarding intercultural education and contributes to resolving theoretical, methodological, and practical issues of research on intercultural competencies.+repphzhbib2018

Effective QCD Partition Function in Sectors with Non-Zero Topological Charge and Itzykson-Zuber Type Integral

It was conjectured by Jackson et.al. that the finite volume effective partition function of QCD with the topological charge $M-N$ coincides with the Itzyskon-Zuber type integral for $M\times N$ rectangular matrices. In the present article we give a proof of this conjecture, in which the original Itzykson-Zuber integral is utilized.Comment: 7pages, LaTeX2