Quantum tasks require islands on the brane
Abstract
In recent work, it was argued that quantum computations with inputs and outputs distributed in spacetime, or quantum tasks, impose constraints on entanglement in holographic theories. The resulting constraint was named the connected wedge theorem and can be verified by a direct bulk proof using focusing arguments in general relativity. In this article we extend this work to the context of AdS/BCFT, where an endoftheworld brane is present in the bulk. By considering quantum tasks which exploit information localized to the brane, we find a new connected wedge theorem. We apply this theorem to brane models of black holes, where it relates the formation of islands in the RyuTakayanagi formula to causal features of the ambient spacetime. In particular, we find that if the black hole interior is causally connected to the radiation system through the ambient spacetime, then an island forms. For constant tension branes in pure AdS the converse also holds.
 Publication:

Classical and Quantum Gravity
 Pub Date:
 July 2021
 DOI:
 10.1088/13616382/ac025d
 arXiv:
 arXiv:2102.01810
 Bibcode:
 2021CQGra..38n4001M
 Keywords:

 AdS/CFT;
 black holes;
 quantum information;
 general relativity;
 High Energy Physics  Theory;
 General Relativity and Quantum Cosmology;
 Quantum Physics
 EPrint:
 v4: typo fixes