Gravity as a worldsheet theory Seminar

Over the past ten years, increasingly simple expressions for the tree-level S-matrix of (super)gravity have been found. These amplitude expressions, which are totally unexpected from a space-time Lagrangian point-of-view, should be telling us something about GR as a non-linear field theory, namely, that it is simpler on-shell than the Einstein-Hilbert action makes it seem. Building from these advances in scattering amplitudes, I will show that GR (or more generally, type II SUGRA in 10d) can be formulated as a worldsheet CFT which is basically free. This story is analogous to, but also crucially different from, the way in which non-linear target space field equations emerge from string theory.