Experimental Investigation of an Eight Qubit Unit Cell in a Superconducting Optimization Processor

TL;DR

This paper reports on the experimental testing of an eight-qubit superconducting quantum processor designed for adiabatic quantum optimization, demonstrating its capabilities and challenges in solving Ising problems.

Contribution

It presents the design, implementation, and characterization of an eight-qubit superconducting chip tailored for adiabatic quantum optimization.

Findings

Successful solution of random Ising spin glass instances

Data aligns with quantum mechanical models including thermal effects

Identifies practical challenges in scaling quantum processors

Abstract

A superconducting chip containing a regular array of flux qubits, tunable interqubit inductive couplers, an XY-addressable readout system, on-chip programmable magnetic memory, and a sparse network of analog control lines has been studied. The architecture of the chip and the infrastructure used to control it were designed to facilitate the implementation of an adiabatic quantum optimization algorithm. The performance of an eight-qubit unit cell on this chip has been characterized by measuring its success in solving a large set of random Ising spin glass problem instances as a function of temperature. The experimental data are consistent with the predictions of a quantum mechanical model of an eight-qubit system coupled to a thermal environment. These results highlight many of the key practical challenges that we have overcome and those that lie ahead in the quest to realize a functional large scale adiabatic quantum information processor.