Robust shaped pulses for arrays of superconducting or semiconductor spin qubits with fixed Ising coupling

Abstract

A major current challenge in solid-state quantum computing is to scale qubit arrays to a larger number of qubits. This is hampered by the complexity of the control wiring for the large number of independently tunable interqubit couplings within these arrays. One approach to simplifying the problem is to use a qubit array with fixed Ising ($ZZ$) interactions. When simultaneously driving a specific subset of qubits in such a system, the dynamics are confined to a set of commuting $\mathfrak{su}$(2) subalgebras. Within these $\mathfrak{su}$(2)s we describe how to perform $X$-gates and $\frac{\pi}{2}$ $ZZ$ rotations robustly against either leakage, which is the main source of error in transmon qubits, or coupling fluctuations, which is the main source of infidelity in flux or semiconductor spin qubits. These gates together with virtual-$z$ gates form a universal set of gates for quantum computing. We construct this set of robust gates for two-edge, three-edge, and four-edge vertices, which compose all existing superconducting qubit and semiconductor spin qubit arrays.