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

It has been shown that multiway junctions gluing n copies of locally AdS 3 spacetimes (n at least 2) can be described by n-1 strings obeying non-linear Nambu-Goto equations coupled by Monge-Ampère 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.