Demonstrating scalable synthesis of multi-qubit gates

Multi-qubit entangling gates are essential in many quantum applications. Although arbitrary quantum gates can be decomposed into sequences of universal single- and two-qubit gates, the huge cost in circuit depth obstructs any meaningful operation within limited coherence time. We propose a scalable method for low-depth synthesis of multi-qubit controlled gates, based on a hardware-efficient construction of quantum AND logic. We successfully demonstrate Toffoli gates with up to 8 qubits on a few-IO, low-crosstalk superconducting quantum processor. We also test our gates in Grover's search algorithm with multiple amplification cycles.