Decoding multiway gravitational junctions in AdS in terms of holographic quantum maps

TL;DR

This paper explores how multiway gravitational junctions in AdS can be understood as interfaces between holographic conformal theories, with dual quantum maps characterized by scattering matrices and automorphisms of the Virasoro algebra.

Contribution

It introduces a holographic interpretation of multiway junctions as quantum interfaces, extending previous 2-way junction results to n-way configurations.

Findings

Dual interfaces correspond to quantum maps factorized into scattering matrices and automorphisms.

These maps are universal, independent of background state modifications.

The study connects gravitational scattering at junctions with conformal field theory automorphisms.

Abstract

It has been shown that multiway junctions gluing $n$ copies of locally AdS$_3$ spacetimes ($n\geq 2$) can be described by $n-1$ strings obeying non-linear Nambu-Goto equations coupled by Monge-Amp\`{e}re like terms. Here we study how such junctions along with their stringy degrees of freedom can be interpreted in terms of an interface between $n$ identical holographic conformal theories each defined on a semi-infinite line (wire). We study the gravitational scattering problem at the multiway junction, and show that at the linearized order the dual interfaces correspond to quantum maps which factorize into a product of a scattering matrix determined only by the tension of the dual junction and relative automorphisms of the Virasoro algebra governed by the $n-1$ stringy modes. Both of these are universal in the sense that they are independent of linear modifications of the background state. These generalize earlier results for the 2-way junctions implying that the dual interface is a tunable energy transmitter. We comment on understanding the quantum map corresponding to the full non-linear gravitational problem, and study Ward identities and unitarity bounds.