No Arabic abstract
Using supersymmetric localization, we study the sector of chiral primary operators $({rm Tr} , phi^2 )^n$ with large $R$-charge $4n$ in $mathcal{N}=2$ four-dimensional superconformal theories in the weak coupling regime $grightarrow 0$, where $lambdaequiv g^2n$ is kept fixed as $ntoinfty $, $g$ representing the gauge theory coupling(s). In this limit, correlation functions $G_{2n}$ of these operators behave in a simple way, with an asymptotic behavior of the form $G_{2n}approx F_{infty}(lambda) left(frac{lambda}{2pi e}right)^{2n} n^alpha $, modulo $O(1/n)$ corrections, with $alpha=frac{1}{2} mathrm{dim}(mathfrak{g})$ for a gauge algebra $mathfrak{g}$ and a universal function $F_{infty}(lambda)$. As a by-product we find several new formulas both for the partition function as well as for perturbative correlators in ${cal N}=2$ $mathfrak{su}(N)$ gauge theory with $2N$ fundamental hypermultiplets.
We study the two-point correlation functions of chiral/anti-chiral operators in $N=2$ supersymmetric Yang-Mills theories on $R^4$ with gauge group SU(N) and $N_f$ massless hypermultiplets in the fundamental representation. We compute them in perturbation theory, using dimensional regularization up to two loops, and show that field-theory observables built out of dimensionless ratios of two-point renormalized correlators on $R^4$ are in perfect agreement with the same quantities computed using localization on the four-sphere, even in the non-conformal case $N_f ot=2N$.
We obtain the perturbative expansion of the free energy on $S^4$ for four dimensional Lagrangian ${cal N}=2$ superconformal field theories, to all orders in the t Hooft coupling, in the planar limit. We do so by using supersymmetric localization, after rewriting the 1-loop factor as an effective action involving an infinite number of single and double trace terms. The answer we obtain is purely combinatorial, and involves a sum over tree graphs. We also apply these methods to the perturbative expansion of the free energy at finite $N$, and to the computation of the vacuum expectation value of the 1/2 BPS circular Wilson loop, which in the planar limit involves a sum over rooted tree graphs.
We compute the planar limit of both the free energy and the expectation value of the $1/2$ BPS Wilson loop for four dimensional ${cal N}=2$ superconformal quiver theories, with a product of SU($N$)s as gauge group and bi-fundamental matter. Supersymmetric localization reduces the problem to a multi-matrix model, that we rewrite in the zero-instanton sector as an effective action involving an infinite number of double-trace terms, determined by the relevant extended Cartan matrix. We find that the results, as in the case of $mathcal{N}=2$ SCFTs with a simple gauge group, can be written as sums over tree graphs. For the $widehat{A_1}$ case, we find that the contribution of each tree can be interpreted as the partition function of a generalized Ising model defined on the tree; we conjecture that the partition functions of these models defined on trees satisfy the Lee-Yang property, i.e. all their zeros lie on the unit circle.
Recently it was argued that the exact R charge for three dimensional N=2 supersymmetric field theories extremizes the partition function localized on S^3. In this paper we check this conjecture by computing the R charge for SU(N)_k YM CS gauge theories at large k for many representations, and we test the agreement with the perturbative results.
We consider a family of $mathcal{N}=2$ superconformal field theories in four dimensions, defined as $mathbb{Z}_q$ orbifolds of $mathcal{N}=4$ Super Yang-Mills theory. We compute the chiral/anti-chiral correlation functions at a perturbative level, using both the matrix model approach arising from supersymmetric localisation on the four-sphere and explicit field theory calculations on the flat space using the $mathcal{N}=1$ superspace formalism. We implement a highly efficient algorithm to produce a large number of results for finite values of $N$, exploiting the symmetries of the quiver to reduce the complexity of the mixing between the operators. Finally the interplay with the field theory calculations allows to isolate special observables which deviate from $mathcal{N}=4$ only at high orders in perturbation theory.