Higher-spin correlators

We analyze the properly normalized three-point correlator of two protected scalar operators and one higher spin twist-two operator in N=4 super Yang-Mills, in the limit of large spin j. The relevant structure constant can be extracted from the OPE of the four-point correlator of protected scalar operators. We show that crossing symmetry of the four point correlator plus a judicious guess for the perturbative structure of the three-point correlator, allow to make a prediction for the structure constant at all loops in perturbation theory, up to terms that remain finite as the spin becomes large. Furthermore, the expression for the structure constant allows to propose an expression for the all loops four-point correlator G(u,v), in the limit u,v -> 0. Our predictions are in perfect agreement with the large j expansion of results available in the literature.Comment: 14 pages,v2:minor changes, refs adde

The superconformal bootstrap for structure constants

We report on non-perturbative bounds for structure constants on N=4 SYM. Such bounds are obtained by applying the conformal bootstrap recently extended to superconformal theories. We compare our results with interpolating functions suitably restricted by the S-duality of the theory. Within numerical errors, these interpolations support the conjecture that the bounds found in this paper are saturated at duality invariant values of the coupling. This extends recent conjectures for the anomalous dimension of leading twist operators.Comment: 14 pages, 4 figure

Modular interpolating functions for N=4 SYM

We construct interpolating functions fully compatible with S-duality. We then consider the problem of resumming perturbative expansions for anomalous dimensions of low twist non-protected operators in N=4 super Yang-Mills theory. When the rank of the gauge group is small, the interpolations suggest that anomalous dimensions of leading twist operators take their maximum value at the point $\tau =\exp(i\pi/3)$. For fixed spin and large enough rank, there is a level-crossing region, where the anomalous dimension of the leading twist operator reaches its maximum and then bounces back.Comment: 13 pages, 5 figures; v2: comments adde

Loop Corrections to Supergravity on AdS5×S5AdS_5 \times S^5

We consider the four-point correlator of the stress-energy tensor multiplet in ${\cal N}=4$ SYM. In the planar limit and at large 't Hooft coupling such correlator is given by the corresponding holographic correlation function in IIB supergravity on $AdS_5 \times S^5$. We consider subleading corrections in the number of colours, i.e. order $1/N^4$, at large 't Hooft coupling. This corresponds to loop corrections to the supergravity result. Consistency conditions, most notably crossing symmetry, constrain the form of such corrections and lead to a complete determination of the spectrum of leading twist intermediate operators.Comment: 6 pages, minor changes, added reference

Generalized bootstrap equations for N=4 SCFT

We study the consistency of four-point functions of half-BPS chiral primary operators of weight p in four-dimensional N=4 superconformal field theories. The resulting conformal bootstrap equations impose non-trivial bounds for the scaling dimension of unprotected local operators transforming in various representations of the R-symmetry group. These bounds generalize recent bounds for operators in the singlet representation, arising from consistency of the four-point function of the stress-energy tensor multiplet.Comment: 18 pages, 3 figure

More alike than different: : the Spanish and Irish labour markets before and after the crisis

This paper analyses the labour markets of Spain and Ireland, which have experienced a severe downturn in the recent global crisis as reflected by the largest increases in their unemployment rates among other developed economies. Spain and Ireland might seem at first to feature very different labour markets, which go from very tight to very flexible labour conditions. Our analysis, however, goes beyond this simplistic argument and brings to light the strong commonalities that seem to have been hidden underground. We estimate a dynamic multi-equation structural model for each country, and then offer two sets of dynamic simulations which account for the swings of the unemployment rates before and after the 2007 crisis. Our results suggest looking beyond the degree of flexibility of both labour markets, just to focus instead on other variables usually neglected by more conventional approaches. In particular, such variables as the growth of capital stock, the growth of labour productivity, and demographics, succeed in explaining a great part of the changes in unemployment in both countries.Este documento analiza los mercados laborales de España e Irlanda, que experimentaron una severa desaceleración en la reciente crisis mundial, como lo reflejan los mayores incrementos en sus tasas de desempleo entre otras economías desarrolladas. Al principio, España e Irlanda parecen tener mercados laborales muy diferentes, que van desde condiciones de trabajo muy ajustadas hasta condiciones laborales muy flexibles. Este análisis, sin embargo, va más allá de este argumento simplista y saca a la luz las fuertes similitudes que parecen haberse ocultado bajo tierra. Se estima un modelo estructural dinámico de multi-ecuaciones para cada país, y luego se ofrecen dos conjuntos de simulaciones dinámicas que dan cuenta de las oscilaciones de las tasas de desempleo antes y después de la crisis de 2007. Estos resultados sugieren mirar más allá del grado de flexibilidad de ambos mercados laborales, solo para centrarse en otras variables generalmente descuidadas por los enfoques más convencionales. En particular, variables tales como el crecimiento del stock de capital, el crecimiento de la productividad laboral y la demografía, logran explicar una gran parte de los cambios en el desempleo en ambos países.Fil: Agnese Pablo .Fil: Salvador Pablo F.. CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas) - Universidad Nacional de Cuyo

More Alike than Different: The Spanish and Irish Labour Markets Before and After the Crisis

This paper analyses the labour markets of Spain and Ireland, which have experienced a severe downturn in the recent global crisis as reflected by the largest increases in their unemployment rates among other developed economies. Spain and Ireland might seem at first to feature very different labour markets, which go from very tight to very flexible labour conditions. Our analysis, however, goes beyond this simplistic argument and brings to light the strong commonalities that seem to have been hidden underground. We estimate a dynamic multi-equation structural model for each country, and then offer two sets of dynamic simulations which account for the swings of the unemployment rates before and after the 2007 crisis. Our results suggest looking beyond the degree of flexibility of both labour markets, just to focus instead on other variables usually neglected by more conventional approaches. In particular, such variables as the growth of capital stock, the growth of labour productivity, and demographics, succeed in explaining a great part of the changes in unemployment in both countries.chain reaction theory, structural multi-equation models, unemployment dynamics, simulations, PIGS

Sulla possibilit\ue0 di estendere l'informazione climatica del passato attraverso le serie dendrocronologiche

In the paper tree-ring index series obtained by 15 Pino Laricio individuals from Etna Volcano in Sicily was used in order to reconstruct the past climate. The significative relation founded between minimun temperature and tree-ring index have enable to reconstruct the minimum temperature series up to the 1790

Dual geometries and spacetime singularities

The notion of geometrical duality is discussed in the context of both Brans-Dicke theory and general relativity. It is shown that, in some particular solutions, the spacetime singularities that arise in usual Riemannian general relativity may be avoided in its dual representation (Weyl-type general relativity). This dual representation provides a singularity-free picture of the World that is physicaly equivalent to the canonical general relativistic one.Comment: 11 pages, LaTeX, no figures, version accepted for publication in PR