Stringy ER=EPR

TL;DR

This paper provides a microscopic string theory perspective on the ER=EPR conjecture, relating entangled disconnected spacetimes to connected black holes through worldsheet dualities and Lorentzian continuations.

Contribution

It constructs explicit string theory examples demonstrating ER=EPR, using Lorentzian continuations of known dualities and novel worldsheet interpretations of Euclidean operators.

Findings

String theory examples of ER=EPR with dual descriptions

Lorentzian continuation of FZZ duality relates connected and disconnected geometries

Entangled string condensates replace horizons in disconnected descriptions

Abstract

The ER = EPR correspondence relates a superposition of entangled, disconnected spacetimes to a connected spacetime with an Einstein-Rosen bridge. We construct examples in which both sides may be described by weakly-coupled string theory. The relation between them is given by a Lorentzian continuation of the FZZ duality of the two-dimensional Euclidean black hole CFT in one example, and in another example by continuation of a similar duality that we propose for the asymptotic Euclidean AdS3 black hole. This gives a microscopic understanding of ER = EPR: one has a worldsheet duality between string theory in a connected, eternal black hole, and in a superposition of disconnected geometries in an entangled state. The disconnected description includes a condensate of entangled folded strings emanating from a strong-coupling region in place of a horizon. Our construction relies on a Lorentzian interpretation of Euclidean time winding operators via angular quantization, as well as some lesser known worldsheet string theories, such as perturbation theory around a thermofield-double state, which we define using Schwinger-Keldysh contours in target space.