English

Mock Modular Index of M2-M5 Brane System

High Energy Physics - Theory 2017-07-25 v2 Algebraic Geometry Number Theory Representation Theory

Abstract

We present BPS indices of the supergroup WZW models that live on intersecting M2-M5 brane systems. They can encode data of the stretched M2-branes between M5-branes and count the BPS states. They are generally expressed in terms of mock theta functions via the Kac-Wakimoto character formula of the affine Lie superalgebra. We give an explicit expression of the index for the PSL(22)k=1PSL(2|2)_{k=1} WZW model in terms of the second order multi-variable Appell-Lerch sum. It indicates that wall-crossing occurs in the BPS state counting due to the CC-field on the M5-branes.

Cite

@article{arxiv.1612.07565,
  title  = {Mock Modular Index of M2-M5 Brane System},
  author = {Tadashi Okazaki and Douglas J. Smith},
  journal= {arXiv preprint arXiv:1612.07565},
  year   = {2017}
}

Comments

47 pages, 8 figures; v2: references added

R2 v1 2026-06-22T17:32:15.146Z