In the last couple of decades, we have learnt a great deal about quantum gravity and its holographic nature in asymptotically AdS spacetimes. Here, we explore this idea in asymptotically flat spacetimes with the following question: Can an observer on the boundary of the spacetime distinguish between two states that are deemed distinguishable by an observer in the bulk? We argue that semiclassical gravity is an effective tool to answer this question, and extrapolate its results to make a few reasonable assumptions regarding the low energy structure of any complete theory of quantum gravity. Using these, we argue that an asymptotic observer indeed has access to all the information in a theory with only massless bulk excitations, provided they are at the past boundary of future null infinity. We also show that information available in any cut of future null infinity is also available in any later cut, but the converse doesn't hold. Similar results hold for past null infinity. We will comment on several interesting questions that this line of investigation sheds light on.
Event organized by CEICO, Central European Institute for Cosmology and Fundamental Physics.
Please contact Roberto Oliveri or Gizem Sengor for further info.