Gravity as a quantum effect on quantum space-time

The 3+1-dimensional Einstein-Hilbert action is obtained from the 1-loop effective on noncommutative branes in IIB or IKKT matrix model. presence of compact fuzzy extra dimensions ${\cal K}$ as well maximal supersymmetry model essential. E-H can be interpreted interaction with space-time brane via supergravity, and Newton constant determined by Kaluza-Klein scale K}$. bare defines a pre-gravity 2 derivatives less than induced action, governing cosmological regime. perturbative physics confined to brane, which for covariant quantum space-times includes all dof gravity, tower higher-spin modes. vacuum energy given terms symplectic volume form, hence does not act constant.