Spacetime Equals Entanglement

Understand

We study the Hilbert space structure of classical spacetimes under the assumption that entanglement in holographic theories determines semiclassical geometry.

• We show that this simple assumption has profound implications; for example, a superposition of classical spacetimes may lead to another classical spacetime.
• Despite its unconventional nature, this picture admits the standard interpretation of superpositions of well-defined semiclassical spacetimes in the limit that the number of holographic degrees of freedom becomes large.
• We illustrate these ideas using a model for the holographic theory of cosmological spacetimes.