Loop-Based Quantum Architecture Could Process Over 1 Million Qubits At Once


Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

clockSep 26 2017, 15:34 UTC


There are many hardware challenges before quantum computers are a reality, but a team from the University of Tokyo might have found a shortcut to simplify an optical quantum system.

Professor Akira Furusawa and assistant professor Shuntaro Takeda worked out how to have multiple photons go around in a loop circuit indefinitely. This architecture can work on multiple tasks and each light pulse can be manipulated to get readings out. The setup is reported in Physical Review Letters.


The system they envisioned could potentially be capable of processing more than 1 million qubits, the quantum equivalent of the bits of information in computers. This is a very ambitious claim. Alternative architectures using superconducting circuits are currently able to deal with about a dozen qubits.

“We’ll start work to develop the hardware, now that we’ve resolved all problems except how to make a scheme that automatically corrects a calculation error,” Furusawa told the Japan Times.

Back in 2013, the researchers actually constructed an optical quantum computer. It was 4.2 meters long and 1.5 meters wide (13.8 by 4.9 feet) and it was made up by over 500 mirror and lenses. Although the whole machinery was incredibly complex, it could only process a single qubit. To process more, you would need more quantum computers. And clearly a lot of space.


This limitation is what pushed Furusawa and Takaneda into looking at how just a single one of these computers could deal with a huge amount of qubits. The new idea uses a single circuit that would replace the complex system and be scalable to theoretically process 1 million qubits at the same time. If the researchers could actually deliver this it would be a significant leap for quantum technology.

Quantum computers promise to completely revolutionize society. Companies like IBM and Google have estimated that quantum computers could be 100,000 times faster than what we currently have developed. And the speed of their operation means that they can tackle problems that not even the most powerful supercomputer can currently solve.

Many research groups around the world are looking on how to build a reliable and functional quantum computer. There is progress in many areas and in many different approaches. Only a few months ago, the first satellite quantum communication was achieved. The road ahead is still long but researchers are moving steadily forward.


[H/T: Japan Times.]

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