Speaker
Yu Miyauchi
(Keio University)
Description
We study the effects of massive Kaluza–Klein (KK) modes on the two-dimensional effective theory obtained from four-dimensional Einstein–Maxwell theory. We show that the background electric field induces mixing between massive Maxwell KK modes and massless graviphotons, generating corrections to the graviphoton kinetic term at tree level and one loop. In particular, the tree-level correction becomes comparable to the classical contribution near extremality, suggesting that massive KK modes cannot be neglected in this regime.