Holography with null boundaries

A bstract One of the key issues in holography is going beyond AdS and defining quantum gravity in spacetimes with a null boundary. Recent examples of this type involve linear dilaton asymptotics and are related to the $$T\overline{T }$$ deformation. We present a holographic correspondence derived from string theory, which is an example of a kind of celestial holography. The holographic definition is a spacetime non-commutative open string theory supported on D1-D5 branes together with fundamental strings. The gravity solutions interpolate between AdS 3 metrics and six-dimensional metrics. Radiation can escape to null infinity, which makes both the encoding of quantum information in the boundary and the dynamics of black holes quite different from AdS spacetimes.