Efficient three-qubit gates with giant atoms

Realizing high-fidelity multi-qubit gates is essential for advancing quantum computing and simulation, yet current implementations remain limited by hardware complexity, crosstalk, and decoherence. We present an efficient approach to implementing native three-qubit gates using giant artificial atoms: quantum emitters coupled to their environment at multiple spatially separated points. This nonlocal coupling yields interference effects that enable versatile control of qubit–qubit interactions. Utilizing these interference effects, we show that high-fidelity three-qubit gates, including the controlled-CZ-SWAP (CCZS) and dual-iSWAP (DIV), can be realized through simple frequency tuning of the giant atoms without parametric drives or additional hardware. As an application, we demonstrate scalable preparation of three- and five-qubit GHZ states with fidelities above 98% for state-of-the-art transmon qubits. These results establish giant-atom systems as a promising platform for low-depth quantum circuit design, offering a new path toward compact and noise-resilient quantum processors.