Implementing the Quantum von Neumann Architecture with Superconducting Circuits

TL;DR

This paper demonstrates a quantum von Neumann architecture using superconducting circuits, integrating a quantum CPU with memory and executing key quantum algorithms with high fidelity, advancing quantum computing hardware development.

Contribution

It introduces a quantum von Neumann architecture with integrated superconducting qubits and memory, executing important algorithms with notable fidelities, a step towards scalable quantum computers.

Findings

Quantum CPU exchanges data with quantum memory on-chip.

Quantum Fourier transform achieved 66% fidelity.

Toffoli gate achieved 98% phase fidelity.

Abstract

The von Neumann architecture for a classical computer comprises a central processing unit and a memory holding instructions and data. We demonstrate a quantum central processing unit that exchanges data with a quantum random-access memory integrated on a chip, with instructions stored on a classical computer. We test our quantum machine by executing codes that involve seven quantum elements: Two superconducting qubits coupled through a quantum bus, two quantum memories, and two zeroing registers. Two vital algorithms for quantum computing are demonstrated, the quantum Fourier transform, with 66% process fidelity, and the three-qubit Toffoli OR phase gate, with 98% phase fidelity. Our results, in combination especially with longer qubit coherence, illustrate a potentially viable approach to factoring numbers and implementing simple quantum error correction codes.