H-branes and chiral strings

We add a simple boundary term to the Polyakov action and construct a new class of D-branes with a single null direction. On the string world sheet the system is described by a single quantized left-mode sector of a conformal field theory. By a Wick rotation of space-time, we map open strings attached to null branes into chiral closed strings. We suggest that these so-called H-branes describe quantum horizons - black hole, cosmological (de-Sitter), etc. We show how one can get a space/phase space transmutation near the horizon and discuss the new features of boundary states which become squeezed states.