To study D-brane physics, we usually consider either the open string theory or the relevant supergravity background. I will argue that for some purposes, one has to do both. I will describe one example: the computation of the gravitational potential between open strings. As an intermediary step I will discuss a family of supergravity solutions describing open strings in the near-horizon of D3-branes.

Theoretische Natuurkunde, Vrije Universiteit Brussel