Commercially impactful quantum algorithms such as quantum chemistry and Shor’s algorithm require a number of qubits and gates far beyond the capacity of any existing quantum processor. Distributed architectures, which scale horizontally by networking modules, provide a route to commercial utility and will eventually surpass the capability of any single quantum computing module. We propose to classify such architectures as Phase 3 Quantum architectures. Such processors consume remote entanglement distributed between modules to realize distributed quantum logic. Networked quantum computers will therefore require the capability to rapidly distribute high fidelity entanglement between modules.
T centre on silicon photonic chip (A) and teleported gate sequence demonstration setup (B)
In this paper, we presented a first demonstration of distributed entanglement between T centres, one of only a handful of colour centres to achieve remote entanglement. These entangled qubits are on silicon photonic chips, each capable of hosting and controlling thousands of qubits, in separate cryostats and connected by optical fibre. These qubits can be connected via optical fibres, making their operation compatible with optical fibre switch networks, and allowing the system to be extended horizontally to many more modules with high connectivity. The T centre emits in a telecommunications band; this demonstration can therefore be performed over tens or hundreds of kilometres without frequency conversion. This band, the telecom O-band, is emerging as a popular quantum network standard and potentially the future “quantum band”. This entanglement demonstration between remote processors establishes a fundamental building block for a scalable Phase 3 Quantum computer, establishing T centres as a candidate Phase 3 Quantum architecture. Cross-module operations will be essential for the execution of distributed, fault-tolerant quantum algorithms in commercially valuable Phase 3 Quantum computing. Finally, we considered entanglement distribution performance prospects for future T centre devices using the same Barett-Kok entanglement scheme but with a higher degree of chip integration and the best-measured T centre material properties. The achievable rates and fidelities far exceed previous optically distributed entanglement demonstrations. This result unlocks distributed quantum computing in silicon, and a path towards networks of silicon quantum processors performing commercially and socially transformative calculations.
To learn more about Photonic’s demonstration of distributed quantum computing operations, we invite you to read our scientific paper titled “Distributed Quantum Computing in Silicon”
For a less technical audience, we recommend our Distributed Entanglement Whitepaper.