Correlation functions, null polygonal Wilson loops, and local operators

We consider the ratio of the correlation function of n+1 local operators over the correlator of the first n of these operators in planar N=4 super-Yang-Mills theory, and consider the limit where the first n operators become pairwise null separated. By studying the problem in twistor space, we prove that this is equivalent to the correlator of a n-cusp null polygonal Wilson loop with the remaining operator in general position, normalized by the expectation value of the Wilson loop itself, as recently conjectured by Alday, Buchbinder and Tseytlin. Twistor methods also provide a BCFW-like recursion relation for such correlators. Finally, we study the natural extension where n operators become pairwise null separated with k operators in general position. As an example, we perform an analysis of the resulting correlator for k=2 and discuss some of the difficulties associated to fixing the correlator completely in the strong coupling regime.Comment: 34 pages, 6 figures. v2: typos corrected and references added; v3: published versio

On correlation functions of Wilson loops, local and non-local operators

We discuss and extend recent conjectures relating partial null limits of correlation functions of local gauge invariant operators and the expectation value of null polygonal Wilson loops and local gauge invariant operators. We point out that a particular partial null limit provides a strategy for the calculation of the anomalous dimension of short twist-two operators at weak and strong coupling.Comment: 29 pages, 8 figure

The Portuguese long version of the Copenhagen Psychosocial Questionnaire II (COPSOQ II) - a validation study

BACKGROUND: Psychosocial risks are now widely recognised as one of the biggest challenges for occupational safety and health (OSH) and a major public health concern. The aim of this paper is to investigate the Portuguese long version of the Copenhagen Psychosocial Questionnaire II (COPSOQ II), in order to analyse the psychometric properties of the instrument and to validate it. METHODS: The Portuguese COPSOQ II was issued to a total of 745 Portuguese employees from both private and public organisations across several economic sectors at a baseline and then 2 weeks later. Methodological quality appraisal was based on COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) recommendations. An analysis of the psychometric properties of the long version of COPSOQ II (internal consistency, intraclass correlation coefficient, floor and ceiling effects, response rate, missing values, mean and standard deviation, exploratory factor analysis) was performed to determine the validity and reliability of the instrument. RESULTS: The COPSOQ II had a response rate of 60.6% (test) and a follow-up response rate of 59.5% (retest). In general, a Cronbach's alpha of the COPSOQ scales (test and retest) was above the conventional threshold of 0.70. The test-retest reliability estimated by the intraclass correlation coefficient (ICC) showed a higher reliability for most of the scales, above the conventional 0.7, except for eight scales. The proportion of the missing values was less than 1.3%, except for two scales. The average scores and standard deviations showed similar results to the original Danish study, except for eight scales. All of the scales had low floor and ceiling effects, with one exception. Overall, the exploratory factor analysis presented good results in 27 scales assuming a reflective measurement model. The hypothesized factor structure under a reflective model was not supported in 14 scales and for some but not all of these scales the explanation may be a formative measurement model. CONCLUSION: The Portuguese long version of COPSOQ II is a reliable and valid instrument for assessing psychosocial risks in the workplace. Although the results are good for most of the scales, there are those that should be evaluated in greater depth in future studies. This instrument may contribute to the promotion of a healthy working environment and workforce, providing clear benefits for companies and employees.info:eu-repo/semantics/publishedVersio

Correlation function of null polygonal Wilson loops with local operators

We consider the correlator of a light-like polygonal Wilson loop with n cusps with a local operator (like the dilaton or the chiral primary scalar) in planar N =4 super Yang-Mills theory. As a consequence of conformal symmetry, the main part of such correlator is a function F of 3n-11 conformal ratios. The first non-trivial case is n=4 when F depends on just one conformal ratio \zeta. This makes the corresponding correlator one of the simplest non-trivial observables that one would like to compute for generic values of the `t Hooft coupling \lambda. We compute F(\zeta,\lambda) at leading order in both the strong coupling regime (using semiclassical AdS5 x S5 string theory) and the weak coupling regime (using perturbative gauge theory). Some results are also obtained for polygonal Wilson loops with more than four edges. Furthermore, we also discuss a connection to the relation between a correlator of local operators at null-separated positions and cusped Wilson loop suggested in arXiv:1007.3243.Comment: 36 pages, 2 figure

On holographic three point functions for GKP strings from integrability

Adapting the powerful integrability-based formalism invented previously for the calculation of gluon scattering amplitudes at strong coupling, we develop a method for computing the holographic three point functions for the large spin limit of Gubser-Klebanov- Polyakov (GKP) strings. Although many of the ideas from the gluon scattering problem can be transplanted with minor modifications, the fact that the information of the external states is now encoded in the singularities at the vertex insertion points necessitates several new techniques. Notably, we develop a new generalized Riemann bilinear identity, which allows one to express the area integral in terms of appropriate contour integrals in the presence of such singularities. We also give some general discussions on how semiclassical vertex operators for heavy string states should be constructed systematically from the solutions of the Hamilton-Jacobi equation.Comment: 62 pages;v2 Typos and equation (3.7) corrected. Clarifying remarks added in Section 4.1. Published version;v3 Minor errors found in version 2 are corrected. For explanation of the revision, see Erratum published in http://www.springerlink.com/content/m67055235407vx67/?MUD=M

Correlation functions of three heavy operators - the AdS contribution

We consider operators in N=4 SYM theory which are dual, at strong coupling, to classical strings rotating in S^5. Three point correlation functions of such operators factorize into a universal contribution coming from the AdS part of the string sigma model and a state-dependent S^5 contribution. Consequently a similar factorization arises for the OPE coefficients. In this paper we evaluate the AdS universal factor of the OPE coefficients which is explicitly expressed just in terms of the anomalous dimensions of the three operators.Comment: 49 pages, 3 figures; v.2 references corrected; v3: corrected discussion in section 5, results unchange

Wave functions and correlation functions for GKP strings from integrability

We develop a general method of computing the contribution of the vertex operators to the semi-classical correlation functions of heavy string states, based on the state-operator correspondence and the integrable structure of the system. Our method requires only the knowledge of the local behavior of the saddle point configuration around each vertex insertion point and can be applied to cases where the precise forms of the vertex operators are not known. As an important application, we compute the contributions of the vertex operators to the three-point functions of the large spin limit of the Gubser-Klebanov-Polyakov (GKP) strings in $AdS_3$ spacetime, left unevaluated in our previous work [arXiv:1110.3949] which initiated such a study. Combining with the finite part of the action already computed previously and with the newly evaluated divergent part of the action, we obtain finite three-point functions with the expected dependence of the target space boundary coordinates on the dilatation charge and the spin.Comment: 80 pages, 7 figures, v2: typos and minor errors corrected, a reference added, v3: typos and a reference corrected, published versio

The CFT6 origin of all tree-level 4-point correlators in AdS3 x S3

© 2020, The Author(s). We provide strong evidence that all tree-level 4-point holographic correlators in AdS 3× S3 are constrained by a hidden 6D conformal symmetry. This property has been discovered in the AdS 5× S5 context and noticed in the tensor multiplet subsector of the AdS3× S3 theory. Here we extend it to general AdS3× S3 correlators which contain also the chiral primary operators of spin zero and one that sit in the gravity multiplet. The key observation is that the 6D conformal primary field associated with these operators is not a scalar but a self-dual 3-form primary. As an example, we focus on the correlators involving two fields in the tensor multiplets and two in the gravity multiplet and show that all such correlators are encoded in a conformal 6D correlator between two scalars and two self-dual 3-forms, which is determined by three functions of the cross ratios. We fix these three functions by comparing with the results of the simplest correlators derived from an explicit supergravity calculation

Advertisement call of Scinax littoralis and S. angrensis (Amphibia: Anura: Hylidae), with notes on the reproductive activity of S. littoralis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Scinax littoralis and S. angrensis are poorly known Atlantic forest endemic species from the Scinax catharinae group, which is known from southern and southeastern Brazil. Herein, we describe the advertisement calls of these two species and compare them to other species within the S. catharinae group. Additionally, we provide information on breeding sites, and calling activity in S. littoralis. Advertisement calls of S. angrensis and S. littoralis are composed of multi-pulsed notes with multiple frequency bands and frequency modulation. Scinax littoralis has a higher minimum and maximum frequency, and lower dominant frequency than S. angrensis, while Scinax littoralis has a longer call. Scinax littoralis appears to be a habitat generalist, occurring from secondary to mature forests, and breeding both in temporary and in permanent ponds. Male S. littoralis were usually observed calling perched on shrub stems, and displayed satellite behavior when the male density was high.72297308Fundacao Grupo O Boticario de Protecao a Natureza [FBPN-UFPR 623]Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundacao Grupo O Boticario de Protecao a Natureza [FBPN-UFPR 623]FAPESP [2008/50575-1, UNESP/PROPe (edital 05/2012)