Making a Difference on a Global Scale

A New Zealand quantum physicist has been selected by Google Research to help bring the world a step closer to a quantum internet.

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Te Whai Ao  —  Dodd-Walls Centre Principal Investigator, Associate Professor Harald Schwefel of the University of Otago has received $50kUSD from Google’s Academic Research Award programme to further his work in quantum technologies and computing. But Schwefel says this isn’t about the funding boost, as much as what the award will enable and with whom.

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“The Google award means we can advance our fabrication facilities at the University of Otago and it puts us into direct contact with the end users of quantum technology.”

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There’s a global race to develop the first scalable fault tolerant quantum computer and successfully link it to others on a distributed platform. This is fraught with challenges such as the inherent instability of qubits (quantum bits of information), error correction, noise, algorithms, data loading, and especially cooling. Businesses such as Google Quantum AI, Rigetti Computing and IBM Quantum are trying to solve these problems using superconducting microwave circuits.

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Harald Schwefel and his team are working on quantum transduction (or conversion) for networking and scalable quantum computing. In this case, converting a quantum bit from the microwave to the optic domain, where optical fibre networks exist.  

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To operate with the qubit, the system needs to be cooled down to sub-kelvin temperatures to remove any thermal microwave photons. One of the current bottle necks is the number of qubits (currently around 1000) that can fit within one cryostat or cooling system.  

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Simply connecting two quantum computers still requires a sub-kelvin link and connecting two quantum computers at room temperature remains an unsolved problem. Schwefel’s team has demonstrated how to convert microwave photons into the optical domain (known as microwave to optical transduction) where optical fibre links work. To do this, every microwave qubit photon needs to be converted into an optical photon. So far this hasn’t been achieved anywhere in the world.

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“Fabrication limitations stopped us at 0.1% quantum efficiency in the past. With this grant, new facilities at the University of Otago and research funding from the Quantum Technologies Aotearoa programme, we will be reaching around 80% efficiency.

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This is considered a point where true quantum transduction and hence entanglement between two superconducting quantum computers becomes feasible, making the true quantum internet a reality,” Schwefel says.

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In announcing the award, the Google Research website says they expect substantial developments in this area to impact both the design of near-term experiments and future architectures for the Google quantum device.

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“Quantum technology is expected to uniquely benefit from the ability to transmit quantum data collected from the world directly into a quantum computer for processing, in order to learn from quantum data or discover fundamentally new facets of our universe.”

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Key Points

There’s global competition to develop quantum computers at scale and network them, like the internet.

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Harald Schwefel is the only New Zealand-based researcher to receive the first Google Research award in advancing quantum technologies and computing.  See the list of recipients here.

Harald Schwefel’s Project:  Electro-optic microwave to optics transduction (conversion) - reaching 80% efficiency.

The University of Otago hosts the Quantum Technologies Aotearoa (QTA) programme, which is managed by Te Whai Ao  —  Dodd-Walls Centre for Photonic and Quantum Technologies.

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READ MORE: Quantum computers link could ‘change the world’: an interview with Harald Schwefel by John Lewis of the Otago Daily Times.

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