## Thursday, January 16, 2014 ... /////

### ER=EPR trivializes in 3D topological field theories

Today, two papers are related to the information preservation and topology change in quantum gravity.

My former advisor Tom Banks, Willy Fischler, and two junior collaborators discuss the holographic spacetime paradigm and offer some provocative theses about the "mirage becoming a reality" for the infalling observers and "unhappening events" in quantum mechanics.

They talk about similar things to those discussed in some previous blog posts but despite the "corrections" to their model of the black hole interior, I think that some claims they make are still not quite right and several claims that are vague and partly incorrect may be replaced by some "fully provable" and robust ones.

In a very interesting gr-qc paper, John Baez and Jamie Vicary study three-dimensional topological field theories in

Wormholes and Entanglement.
What does Maldacena's and Susskind's ER-EPR correspondence imply in this special context?

Note that in topological field theories, the information about particles is limited. In some sense, the particles don't carry any exact information about their position or momentum. Their existence is just a discrete piece of information. At any rate, there is a way to study the creation of particle-antiparticle pairs.

The authors conclude that such a process is identical to the birth of a wormhole. The entanglement between the particle and the antiparticle takes an extreme form of the "fake entanglement" – the degrees of freedom are just identical (i.e. forced to be entangled even a priori). Unlike the usual entanglement, this "fake entanglement" isn't restricted by the monogamy.

How the ER-EPR correspondence simplifies in similar special situations represents a class of very important questions and I think it's great that Baez and Vicary have attacked one of these questions.

Amusingly enough, they say – as slick politicians – that they would take no side in the firewall argument. They also point out that the ER-EPR doesn't really rely on any special features of the AdS/CFT; I agree with that, ER-EPR is more general (and perhaps "more fundamental") in this conceptual sense.