Strong-coupling results in (non-)conformal 𝒩 = 2 theories with fundamental flavors

A bstract We study a class of four-dimensional 𝒩 = 2 SU( N ) gauge theories with two massless hypermultiplets in the rank-two antisymmetric representation and 0 ≤ N F ≤ 4 fundamental flavors. These theories are superconformal for N F = 4 and asymptotically free otherwise. Supersymmetric localization on the four-sphere applies in both cases and leads to matrix-model representations for a broad class of protected observables. Within this framework, we compute the free energy and the expectation value of the 1/2 1 2 -BPS circular Wilson loop in the large- N limit. For any N F , we show that the infinite series of non-planar corrections at large ’t Hooft coupling λ can be resummed in terms of an effective coupling ~ λ λ ~ . In the non-conformal window (0 ≤ N F < 4), this provides a first example in which localization leads to explicit results in the planar limit at strong ’t Hooft coupling. In the superconformal case ( N F = 4), the large- N expansion in ~ λ λ ~ suggests a refined AdS/CFT dictionary in which ~ λ λ ~ , rather than λ , plays the role of the bulk string coupling.