A Modular Superconducting Qubit Processor via Inter-chip Entanglement

Scaling superconducting qubit based processors to the hundreds and eventually thousands of physical qubits necessary for fault-tolerant computing presents some formidable science and engineering challenges. One of the most fundamental of these challenges is fabrication yield, which decreases exponentially with the number of qubits per chip. A natural solution to this challenge is the assembly of processors out of small, specialized modules with high fidelity, low-latency quantum interconnects between them. In this talk, we will show first demonstrations of this obtained with two different modular chip architectures. We will start with experimental results from a test platform with deterministic inter-module coupling between four physically separate, interchangeable superconducting qubit integrated circuits, achieving two-qubit gate fidelities as high as 99.1 ± 0.5% and 98.3 ± 0.3% for iSWAP and CZ entangling gates, respectively. We will then move on to results from Rigetti's first modular, multi-chip quantum processor consisting of two 40 qubit chips with interchip coupling between the chips. This modular approach, and the inter-module coupling technology which enables it, can accelerate near-term experimental efforts and open up new paths to the fault-tolerant era for solid state qubit architectures.