Supergravity Backgrounds in IIB Matrix Model

Abstract

We construct wave functions and vertex operators in the type IIB matrix model by using a supersymmetric Wilson line operator. It is shown that wave functions can be intepreted as overlaps of the D-instanton boundary states with the closed string massless states. We then calculate the one-loop effective action for N D-instantons under the supergravity backgrounds by integrating out one D-instanton with an appropriate wave function.