Tunable ZZZ Coupler for Quantum Annealing with Superconducting Flux Qubits

Implementations of quantum annealing with superconducting qubits rely on tunable two-body interactions. Having higher order interactions, such as ZZZ coupling, can enable more efficient embedding of hard problems and error suppression schemes. We designed a coupler for high-coherence superconducting flux qubits that mediates a strong tunable ZZZ coupling. We use both the Born-Oppenheimer approximation and exact simulations to understand the interactions mediated by the coupler. We discuss plans for the implementation of this coupler in a quantum annealer. The research is based upon work partially supported by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA), via the U.S. Army Research Office contract W911NF-17-C-0050. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the ODNI, IARPA, or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Governmental purposes notwithstanding any copyright annotation thereon.