Quantum networking chip will enable quantum computers to work together over the internet
Cisco claims its research into quantum computing will speed up the time it will take to develop viable quantum computing applications from decades to just five-to-10 years.
Cisco senior vice president Vijoy Pandey made the claim on the day that the company unveiled its Quantum Network Entanglement chip, a research prototype that, he said, “enables quantum networks to scale and connect quantum processors for practical applications”.
This was developed at the Cisco Quantum Labs facility in Santa Monica, California, which the company formally opened, although Cisco has had a team working on the quantum networking stack for years.
The technology is intended to enable quantum computers to be networked and therefore enable their combined power to be increased from just a few thousand qubits per quantum computer by 2030 to as many as can be networked and scaled together. “It generates pairs of entangled photons that instantly transmit quantum state between each other regardless of distance through quantum teleportation,” claimed Pandey.
Cisco claims its quantum computing chips work over existing fibre-optic network infrastructure, can be deployed and run at room temperature (unlike quantum computers), is energy efficient (also unlike quantum computers) and offers high performance – up to one million high-fidelity entanglement pairs per output channel, with a rate of up to 200 million entanglement pairs per chip per second.
“Beyond the entanglement chip, we’re advancing research prototypes of other critical components including entanglement distribution protocols, a distributed quantum computing compiler, Quantum Network Development Kit (QNDK), and a Quantum Random Number Generator (QRNG) using quantum vacuum noise,” said Pandey.
He added: “In parallel, Cisco teams are implementing post-quantum cryptography (PQC) NIST [US National Institute of Standards and Technology] standards across our portfolio, ensuring classical networks remain secure in a post- quantum world.”
The technical details of the technology are explored in-depth in a research paper published earlier this year. In it, the researchers describe the technology as a “scalable architecture for quantum datacentre networks that distribute entanglement between QPUs [quantum processing units]”.
The paper “introduces an architecture for quantum datacentres. The challenges for quantum datacentre network fabric are fundamentally different from classical ones”, write Reza Nejabati and Ramana Kompella, researchers at Cisco Quantum Research.
They continue: “Quantum datacentres must preserve fragile quantum states, distribute entanglement resources, facilitate teleportation between processors and synchronize operations with sub-nanosecond precision. These capabilities are not in commercial off-the-shelf networking components.”
They propose a triple-layer architecture consisting of a physical layer of specialised quantum hardware, an “entanglement layer” that distributes quantum resources and a compute layer “that partitions algorithms across networked processors”.
This architecture enables multiple smaller quantum processors to work together as a unified system, they argue.
At the heart of this architecture is Cisco’s quantum network entanglement chip, “a quantum networking device that creates pairs of photons that remain connected regardless of distance”.
The research prototype was developed in collaboration with the University of California at Santa Barbara (UC Santa Barbara). It utilises “integrated photonics”, according to Galan Moody, associate professor of Electrical and Computer Engineering at the University campus.
“Integrated photonics enables many sources to be combined onto a single chip, and by packaging these sources with optical fibre and electronic controls, a single device can boost the entanglement rates for many users on their quantum network,” he said.
At the same time, the research centre is also collaborating with a start-up experimenting with rubidium vapour cell technology that bridges different quantum systems that operate in different frequencies. This dual-frequency source creates entangled pairs where one photon operates at near-infra-red frequency (close to most quantum computing platforms) while its partner operates at telecom frequency.
In addition to the quantum chip and networking research, the centre is also developing quantum switches, network interface cards and a distributed computing compiler.
Cisco’s research comes at a time when many major companies are increasing their research into quantum computing, including Boeing, which is planning a quantum satellite network, and Toshiba, which has claimed a breakthrough in supposedly unhackable quantum networking.
In the UK, researchers from the Universities of Bristol and Cambridge earlier this year demonstrated the country’s first long-distance quantum-secured communication network.