Rydberg-atom graphs for quadratic unconstrained binary optimization problems

TL;DR

This paper demonstrates how Rydberg-atom graphs can be used to solve quadratic unconstrained binary optimization problems by encoding them into physical atomic configurations and measuring their ground states, showing a new approach to quantum optimization.

Contribution

The authors introduce four elementary Rydberg-atom subgraph components that simplify encoding QUBO problems and are robust against errors, advancing quantum optimization methods.

Findings

Successful experimental encoding of QUBO problems into Rydberg-atom graphs

Demonstration of measuring many-body ground states to find solutions

Validation of the robustness and programmability of the subgraph components

Abstract

There is a growing interest in harnessing the potential of the Rydberg-atom system to address complex combinatorial optimization challenges. Here we present an experimental demonstration of how the quadratic unconstrained binary optimization (QUBO) problem can be effectively addressed using Rydberg-atom graphs. The Rydberg-atom graphs are configurations of neutral atoms organized into mathematical graphs, facilitated by programmable optical tweezers, and designed to exhibit many-body ground states that correspond to the maximum independent set (MIS) of their respective graphs. We have developed four elementary Rydberg-atom subgraph components, not only to eliminate the need of local control but also to be robust against interatomic distance errors, while serving as the building blocks sufficient for formulating generic QUBO graphs. To validate the feasibility of our approach, we have conducted a series of Rydberg-atom experiments selected to demonstrate proof-of-concept operations of these building blocks. These experiments illustrate how these components can be used to programmatically encode the QUBO problems to Rydberg-atom graphs and, by measuring their many-body ground states, how their QUBO solutions are determined subsequently.