Locality from Quantum Gravity: All or Nothing

Understand

In a full theory of quantum gravity, local physics is expected to be approximate rather than innate.

• It is therefore important to understand how approximate locality emerges in the semiclassical limit.
• Here we show that any notion of locality emergent from a holographic theory of quantum gravity is "all or nothing": local data is not obtained gradually from subregions of the boundary, but is rather obtained all at once when enough of the boundary is accessed.
• Our assumptions are mild and thus this feature is quite general; in the special case of AdS/CFT, a slightly different manifestation follows from well-known and familiar properties.