Abstract
The Ryu-Takayangi formula provides an important relationship between minimal surfaces in the bulk and entanglement entropies of quantum field theories on the boundary. We provide an extension of this formula to asymptotically flat spacetimes. We first do this for the spherically symmetric Schwarzschild metric by gluing copies of SAdS (Schwarzschild-AdS) to either side using the Israel junction conditions. We then discuss the Brill-Lindquist initial data, which describes N colliding black holes that form an (N + 1)-boundary asymptotically flat wormhole geometry on a time symmetric Cauchy slice. We discuss some important properties and useful coordinates to study the metric, before exploring numerical meth- ods to compute and classify its extremal surfaces. This leads us into applying our RT extension to the asymptotically flat wormholes generated by the Brill-Lindquist metric. An example of this application is explored within the ER=EPR framework, where we study a holographic model for black hole evaporation by taking the Brill-Lindquist wormhole to represent the entanglement geometry of the evaporation pro- cess. The Page curve for the entanglement entropy is recovered for N = 2 and we also discuss properties of the Python’s lunch proposal within this model.