Horizon Branes and Chiral Strings

In this thesis I present a new type of brane - H-brane - where the role of time in String Theory is considered as a primary concept in the search for still unknown black hole physics. Using the basic tools of boundary conformal field theory, we describe the H-branes both in the open and closed string channels and examine how they fit naturally in the known D-brane moduli space. In particular we compute their Ishibashi states and quantize the system using the first order formalism. We find that the geometry associated to the target null coordinates is non-commutative.