4-bit Factorization Circuit Composed of Multiplier Units with Superconducting Flux Qubits toward Quantum Annealing

TL;DR

This paper demonstrates a 4-bit prime factorization circuit using superconducting flux qubits designed for quantum annealing, showcasing a scalable approach with fewer qubits than traditional methods, validated through experiments and simulations.

Contribution

It introduces a superconducting quantum circuit implementing a multiplier Hamiltonian for factorization, with a novel scalable design using fewer qubits than conventional architectures.

Findings

Successful 4-bit factorization experiments at 10 mK and 4.2 K

Demonstrated scalability with fewer qubits than chimera graph methods

Validated interconnection of multiplier units through experiments and simulations

Abstract

Prime factorization (P = M*N) is considered to be a promising application in quantum computations. We perform 4-bit factorization in experiments using a superconducting flux qubit toward quantum annealing. Our proposed method uses a superconducting quantum circuit implementing a multiplier Hamiltonian, which provides combinations of M and N as a factorization solution after quantum annealing when the integer P is initially set. The circuit comprises multiple multiplier units combined with connection qubits. The key points are a native implementation of the multiplier Hamiltonian to the superconducting quantum circuit and its fabrication using a Nb multilayer process with a Josephson junction dedicated to the qubit. The 4-bit factorization circuit comprises 32 superconducting flux qubits. Our method has superior scalability because the Hamiltonian is implemented with fewer qubits than in conventional methods using a chimera graph architecture. We perform experiments at 10 mK to clarify the validity of interconnections of a multiplier unit using qubits. We demonstrate experiments at 4.2 K and simulations for the factorization of integers 4, 6, and 9.