A Non-perturbative Description of the Gimon-Polchinski Orientifold

TL;DR

This work provides a non-perturbative description of a T-dual Gimon-Polchinski orientifold by modeling the varying axion-dilaton $oldsymbol{ au}(u,v)$ through a Weierstrass form $y^2=x^3+f(u,v)x+g(u,v)$ with discriminant $oldsymbol{ riangle}=4f^3+27g^2$ and modular relation $j(oldsymbol{ au})=rac{4(24f)^3}{4f^3+27g^2}$. By enforcing positivity of $ ext{Im}(oldsymbol{ au})$ and SL$(2,Z)$ monodromies, and matching large-$u$ and large-$v$ limits to Seiberg–Witten data for SU(2) with four flavors, the authors construct polynomial $f$ and $g$ that realize several non-perturbative backgrounds. They derive explicit solutions corresponding to multiple gauge configurations (e.g., $U(4)_v imes U(4)_u$, $SU(2)_v imes SU(2)'_v imes U(4)_u$, $Sp(4)_v imes Sp(4)_u$, and their mixtures), showing that orientifold planes split into brane pairs that generically join smoothly into a single seven-brane, except in special loci. The deformation parameter $oldsymbol{eta}$ is tied to twisted-sector blow-up moduli, and turning on hypermultiplet vevs in the $(4,4)$ representation provides a controlled way to further deform or break the gauge symmetry while preserving consistency with monodromy constraints. Overall, the work offers a coherent non-perturbative, brane-probe perspective on the GP orientifold and its moduli, highlighting how quantum effects reorganize brane configurations and their effective couplings.

Abstract

A T-dual version of the Gimon-Polchinski orientifold can be described by a configuration of intersecting Dirichlet seven branes and orientifold seven planes in the classical limit. We study modification of this background due to quantum corrections. It is shown that non-perturbative effects split each orientifold plane into a pair of nearly parallel seven branes. Furthermore, a pair of intersecting orientifold planes, instead of giving rise to two pairs of intersecting seven branes, gives just one pair of seven branes, each representing a pair of nearly orthogonal seven branes smoothly joined to each other near the would be intersection point. Interpretation of these results from the point of view of the dynamics on a three brane probe is also discussed.