Speaker
Guglielmo Lockhart
Description
I will discuss a class of 2d NLSMs which describe D3 branes wrapped on a two-sphere and probing an F-theory singularity. The chiral algebras of the NLSMs turn out to be a very useful tool. For one choice of twisting, the resulting NLSMs describe 6d instanton strings, and the chiral algebras encode BPS invariants of elliptic threefolds. A different choice of twist leads to NSLMs on minuscule varieties; in one notable example, the chiral algebra of the NLSM describes the ghost sector of the pure spinor superstring, and our construction reveals the existence of a hidden E6 symmetry.
