I-Brane Dynamics

TL;DR

This paper investigates the dynamics of intersecting fivebranes in type IIB string theory using both open and closed string descriptions, revealing different supersymmetry properties and the role of anomaly inflow in understanding the system.

Contribution

It provides a comparative analysis of weak and strong coupling descriptions of intersecting fivebranes, highlighting the impact of anomaly inflow on the system's behavior.

Findings

Weak coupling: invariant under eight supercharges with chiral fermions at the intersection.

Strong coupling: three-dimensional Poincare invariant theory with sixteen supercharges.

Anomaly inflow explains the transition between the two descriptions.

Abstract

We study the dynamics near a 1+1 dimensional intersection of two orthogonal stacks of fivebranes in type IIB string theory, using an open string description valid at weak coupling, and a closed string description valid at strong coupling. The weak coupling description suggests that this system is invariant under eight supercharges with a particular chirality in 1+1 dimensions, and its spectrum contains chiral fermions localized at the intersection. The closed string description leads to a rather different picture -- a three dimensional Poincare invariant theory with a gap and sixteen supercharges. We show that this dramatic change in the behavior of the system is partly due to anomaly inflow. Taking it into account leads to a coherent picture, both when the fivebranes in each stack are coincident and when they are separated.