Fast microwave-driven three-qubit gates for cavity-coupled superconducting qubits

TL;DR

This paper presents a method for implementing fast, high-fidelity three-qubit gates in superconducting qubits using microwave pulses, which simplifies quantum error correction and enhances quantum computing efficiency.

Contribution

The authors design and optimize microwave-driven three-qubit gates for transmon qubits, achieving high speed and fidelity with simple pulse shapes, especially when interqubit frequency differences are small.

Findings

Three-qubit ccz gate performed in 260 ns

Gate fidelities exceed 99.38% with analytical pulses

Fidelities reach 99.99% with numerical optimization

Abstract

Although single and two-qubit gates are sufficient for universal quantum computation, single-shot three-qubit gates greatly simplify quantum error correction schemes and algorithms. We design fast, high-fidelity three-qubit entangling gates based on microwave pulses for transmon qubits coupled through a superconducting resonator. We show that when interqubit frequency differences are comparable to single-qubit anharmonicities, errors occur primarily through a single unwanted transition. This feature enables the design of fast three-qubit gates based on simple analytical pulse shapes that are engineered to minimize such errors. We show that a three-qubit ccz gate can be performed in 260 ns with fidelities exceeding $99.38\%$, or $99.99\%$ with numerical optimization.