Quantum walks on a programmable two-dimensional 62-qubit superconducting processor

TL;DR

This paper demonstrates high-fidelity quantum walks and interferometry on a 62-qubit superconducting processor, showcasing its potential for quantum simulations and algorithms on intermediate-scale quantum hardware.

Contribution

The work presents the design, fabrication, and experimental demonstration of quantum walks and interferometry on a large 62-qubit superconducting array, advancing programmable quantum processors.

Findings

High fidelity single and two-particle quantum walks achieved

Implementation of a Mach-Zehnder interferometer on a superconducting processor

Observation of interference fringes with controlled disorder

Abstract

Quantum walks are the quantum mechanical analogue of classical random walks and an extremely powerful tool in quantum simulations, quantum search algorithms, and even for universal quantum computing. In our work, we have designed and fabricated an 8x8 two-dimensional square superconducting qubit array composed of 62 functional qubits. We used this device to demonstrate high fidelity single and two particle quantum walks. Furthermore, with the high programmability of the quantum processor, we implemented a Mach-Zehnder interferometer where the quantum walker coherently traverses in two paths before interfering and exiting. By tuning the disorders on the evolution paths, we observed interference fringes with single and double walkers. Our work is an essential milestone in the field, brings future larger scale quantum applications closer to realization on these noisy intermediate-scale quantum processors.