Quantum Gates to other Universes
Constantin Bachas, Ioannis Lavdas
TL;DR
This work builds a holographic model in which two AdS4 universes are joined by a microscopic gate, a low-rank gauge group acting as a messenger, with the dual gravity description featuring a short AdS5×S5 throat carrying $n$ flux units. The authors derive a universal graviton-mass mixing relation $M^2 \simeq {3 n^2 (\kappa_4^2 + \kappa_4'^{2}) \over 16\pi^2}$, which reduces to $M^2 \simeq {3 \over 8\pi^2} \kappa_4^2 n^2$ for identical universes, and show that the effective coupling is quantized—paralleling double-trace deformations but preserving locality once the gate is integrated back. The holographic construction uses partitions of good 3d ${\cal N}=4$ quivers, realized as Type-IIB solutions with harmonic functions $h_1,h_2$, and the gate is implemented by a rearrangement of $n$ boxes in the quiver diagrams, corresponding to a calculable AdS5 throat geometry. The results bridge field-theoretic double-trace intuition and a local, semiclassical gravitational mechanism for inter-Universe coupling, with extensions to non-identical universes and potential worldsheet interpretations of gates.
Abstract
We present a microscopic model of a bridge connecting two large Anti-de-Sitter Universes. The Universes admit a holographic description as three-dimensional ${\cal N}=4$ supersymmetric gauge theories based on large linear quivers, and the bridge is a small rank-$n$ gauge group that acts as a messenger. On the gravity side, the bridge is a piece of a highly-curved AdS$_5\times$S$_5$ throat carrying $n$ units of five-form flux. We derive a universal expression for the mixing of the two massless gravitons: $M^2 \simeq 3n^2 (κ_4^2 + κ_4^{\prime\,2})/16π^2$, where $M$ is the mass splitting of the gravitons, $κ_4^2, κ_4^{\prime\,2}$ are the effective gravitational couplings of the AdS$_4$ Universes, and $n$ is the quantized charge of the gate. This agrees with earlier results based on double-trace deformations, with the important difference that the effective coupling is here quantized. We argue that the apparent non-localities of holographic double-trace models are resolved by integrating-in the (scarce) degrees of freedom of the gate.
