Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userRevisiting instanton corrections to the Konishi multiplet
178
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We revisit the calculation of instanton effects in correlation functions in ${cal N}=4$ SYM involving the Konishi operator and operators of twist two. Previous studies revealed that the scaling dimensions and the OPE coefficients of these operators do not receive instanton corrections in the semiclassical approximation. We go beyond this approximation and demonstrate that, while operators belonging to the same ${cal N}=4$ supermultiplet ought to have the same conformal data, the evaluation of quantum instanton corrections for one operator can be mapped into a semiclassical computation for another operator in the same supermultiplet. This observation allows us to compute explicitly the leading instanton correction to the scaling dimension of operators in the Konishi supermultiplet as well as to their structure constants in the OPE of two half-BPS scalar operators. We then use these results, together with crossing symmetry, to determine instanton corrections to scaling dimensions of twist-four operators with large spin.
rate research
Read More
We present the calculation of the leading instanton contribution to the scaling dimensions of twist-two operators with arbitrary spin and to their structure constants in the OPE of two half-BPS operators in $mathcal N=4$ SYM. For spin-two operators we verify that, in agreement with $mathcal N=4$ superconformal Ward identities, the obtained expressions coincide with those for the Konishi operator. For operators with high spin we find that the leading instanton correction vanishes. This arises as the result of a rather involved calculation and requires a better understanding.
We discuss a string model where a conformal four-dimensional N=2 gauge theory receives corrections to its gauge kinetic functions from stringy instantons. These contributions are explicitly evaluated by exploiting the localization properties of the integral over the stringy instanton moduli space. The model we consider corresponds to a setup with D7/D3-branes in type I theory compactified on T4/Z2 x T2, and possesses a perturbatively computable heterotic dual. In the heteoric side the corrections to the quadratic gauge couplings are provided by a 1-loop threshold computation and, under the duality map, match precisely the first few stringy instanton effects in the type I setup. This agreement represents a very non-trivial test of our approach to the exotic instanton calculus.
We consider the non-perturbative superpotential for a class of four-dimensional $mathcal N=1$ vacua obtained from M-theory on seven-manifolds with holonomy $G_2$. The class of $G_2$-holonomy manifolds we consider are so-called twisted connected sum (TCS) constructions, which have the topology of a K3-fibration over $S^3$. We show that the non-perturbative superpotential of M-theory on a class of TCS geometries receives infinitely many inequivalent M2-instanton contributions from infinitely many three-spheres, which we conjecture are supersymmetric (and thus associative) cycles. The rationale for our construction is provided by the duality chain of arXiv:1708.07215, which relates M-theory on TCS $G_2$-manifolds to $E_8times E_8$ heterotic backgrounds on the Schoen Calabi-Yau threefold, as well as to F-theory on a K3-fibered Calabi-Yau fourfold. The latter are known to have an infinite number of instanton corrections to the superpotential and it is these contributions that we trace through the duality chain back to the $G_2$-compactification.
The spin chain formulation of the operator spectrum of the N=4 super Yang-Mills theory is haunted by the problem of ``wrapping, i.e. the inapplicability of the formalism for short spin chain length at high loop-order. The first instance of wrapping concerns the fourth anomalous dimension of the Konishi operator. While we do not obtain this number yet, we lay out an operational scheme for its calculation. The approach passes through a five- and six-loop sector. We show that all but one of the Feynman integrals from this sector are related to five master graphs which ought to be calculable by the method of partial integration. The remaining supergraph is argued to be vanishing or finite; a numerical treatment should be possible. The number of numerator terms remains small even if a further four-loop sector is included. There is no need for infrared rearrangements.
We present a calculation of the four-loop anomalous dimension of the SU(2) sector Konishi operator in N=4 SYM, as an example of wrapping corrections to the known result for long operators. We use the known dilatation operator at four loops acting on long operator, and just calculate those diagrams which are affected by the change from operator length L > 4 to L = 4. We find that the answer involves a Zeta[5], so it has trancendentality degree five. Our result differs from previous proposals and calculations. We also discuss some ideas for extending this analysis to determine finite size corrections for operators of arbitrary length in the SU(2) sector.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
