Embedding scheme for the maximum-independent-set problem on three-dimensional Rydberg-atom arrays
Phys. Rev. A 113, 062420 – Published 5 June, 2026
DOI: https://doi.org/10.1103/516n-6wtx
Abstract
The Maximum Independent Set (MIS) problem on unit-disk graphs is an NP-hard problem that can be naturally encoded on Rydberg atom systems. While existing mapping schemes enable the encoding of arbitrary graphs, current two-dimensional (2D) embedding approaches have an atom overhead, limiting the size of problems solvable on near-term hardware. In this work, we present a scalable scheme that maps the MIS problem on arbitrary graphs onto programmable three-dimensional (3D) arrays of Rydberg atoms. By utilizing the extra degree of freedom provided by the third dimension, we develop a graph-reduction algorithm that embeds any graph into a 3D unit-disk graph. We show this embedding requires an overhead of atoms, where and denote the number of vertices and edges of the original graph. Furthermore, we prove that our embedding scheme is optimal for both bounded-degree graphs and dense graphs. Benchmarks on 3-regular, Erdős-Rényi, SAT-derived graphs, and standard MIS benchmark sets demonstrate that the required atom count is one to two orders of magnitude lower than state-of-the-art 2D schemes. Our work establishes a practical route toward solving large-scale, classically intractable MIS instances on near-term Rydberg quantum processors.