UNSW Sydney nano-tech startup Diraq has shown its quantum chips aren’t just lab-perfect prototypes – they also hold up in real-world production, maintaining the 99% accuracy needed to make quantum computers viable.
Diraq, a pioneer of silicon-based quantum computing, achieved this feat by teaming up with European nanoelectronics institute Interuniversity Microelectronics Centre (imec). Together they demonstrated the chips worked just as reliably coming off a semiconductor chip fabrication line as they do in the experimental conditions of a research lab at UNSW.
UNSW Engineering Professor Andrew Dzurak, who is the founder and CEO of Diraq, said up until now it hadn’t been proven that the processors’ lab-based fidelity – meaning accuracy in the quantum computing world – could be translated to a manufacturing setting.
“Now it’s clear that Diraq’s chips are fully compatible with manufacturing processes that have been around for decades.”
In a paper published on Sept. 24 in Nature, the teams report that Diraq-designed, imec-fabricated devices achieved over 99% fidelity in operations involving two quantum bits – or ‘qubits’. The result is a crucial step towards Diraq’s quantum processors achieving utility scale, the point at which a quantum computer’s commercial value exceeds its operational cost. This is the key metric set out in the Quantum Benchmarking Initiative, a program run by the United States’ Defense Advanced Research Projects Agency (DARPA) to gauge whether Diraq and 17 other companies can reach this goal.
Utility-scale quantum computers are expected to be able to solve problems that are out of reach of the most advanced high-performance computers available today. But breaching the utility-scale threshold requires storing and manipulating quantum information in millions of qubits to overcome the errors associated with the fragile quantum state.
“Achieving utility scale in quantum computing hinges on finding a commercially viable way to produce high-fidelity quantum bits at scale,” said Prof. Dzurak.
“Diraq’s collaboration with imec makes it clear that silicon-based quantum computers can be built by leveraging the mature semiconductor industry, which opens a cost-effective pathway to chips containing millions of qubits while still maximizing fidelity.”
Silicon is emerging as the front-runner among materials being explored for quantum computers – it can pack millions of qubits onto a single chip and works seamlessly with today’s trillion-dollar microchip industry, making use of the methods that put billions of transistors onto modern computer chips.
Diraq has previously shown that qubits fabricated in an academic laboratory can achieve high fidelity when performing two-qubit logic gates, the basic building block of future quantum computers. However, it was unclear whether this fidelity could be reproduced in qubits manufactured in a semiconductor foundry environment.
“Our new findings demonstrate that Diraq’s silicon qubits can be fabricated using processes that are widely used in semiconductor foundries, meeting the threshold for fault tolerance in a way that is cost-effective and industry-compatible,” Prof. Dzurak said.
Diraq and imec previously showed that qubits manufactured using CMOS processes – the same technology used to build everyday computer chips – could perform single-qubit operations with 99.9% accuracy. But more complex operations using two qubits that are critical to achieving utility scale had not yet been demonstrated.
“This latest achievement clears the way for the development of a fully fault-tolerant, functional quantum computer that is more cost effective than any other qubit platform,” Prof. Dzurak said.
