Fujitsu, RIKEN open Japan's first superconducting quantum 'puter to eggheads

Development of Japan's first superconducting quantum computer is complete, Fujitsu and the country's scientific research institute RIKEN announced this week.

Superconducting quantum computers are among the most common today, and are employed by the likes of Google, IBM, and Rigetti. The design uses superconducting circuits operating at near absolute-zero temperatures to generate qubits.

The Japanese system, now deployed at the RIKEN RQC-Fujitsu Collaboration Center, features 64 superconducting qubits on an integrated chip.

The outfit claims the system is capable of 264 quantum superposition and entanglement states, which it asserts allows the computer to conduct calculations on a scale too challenging for classical computers. That said, the system will run alongside classical computers running quantum simulations to keep it in check.

"Quantum simulators, which can digitally imitate quantum computation, provide a bridge toward the development of practical fault-tolerant quantum computing (FTQC)," Fujitsu explained, noting a fault-tolerant system capable of generating reliable results is likely a decade or more out.

Quantum computers are finicky devices that need a good deal of error correction to be useful; that fault tolerance, allowing the computer to operate in a meaningful way, is a necessity, rather than a luxury, and it's still years away.

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For now, pairing the quantum computer up with an HPC cluster that simulates 40 qubits should help scientists evaluate the system’s ability to reliably generate accurate results.

The problem, Fujitsu explained, is that noisy intermediate-scale quantum (NISQ) computers suffer from computational errors due to noise in the surrounding environment. Quantum simulations aren't prone to these same errors because the qubits aren’t real and are therefore immune to noise disruptions. The downside of quantum simulation is it's rather slow compared to the real thing. And also not the real thing.

Which is not to say that sims and this system aren’t useful. RIKEN and Fujitsu claim the hybrid system has already proven more accurate when applying quantum algorithms to chemical calculations. These calculations are a classic HPC workload and, as we've previously reported, a prime candidate for quantum acceleration in the near term.

An experiment involving this hybrid setup calculated the ground state energy of a molecule containing 12 hydrogen atoms. Using a combination of quantum algorithms, density matrix embedding theory — a method of breaking up large molecules into smaller fragments — and an AI model to help mitigate the effects of noise, Fujitsu and RIKEN say they were able to perform these energy calculations with higher accuracy than when using classical algorithms alone.

With the system now deployed, Fujitsu and RIKEN are now opening it up to outside companies and institutions — including Fujifilm, Tokyo Electron, Mizuho-DL Financial Technology Co., and Mitsubishi Chemical — to conduct joint research.

Fujitsu and RIKEN are already developing technologies necessary to scale the system up to 1,000 qubits, thanks to a vertical wiring scheme that Fujitsu explained on Thursday. ®