Quantum computing infrastructure startup Q-CTRL Pty. Ltd. said today it has closed on a $27.4 million Series B-1 fundraise, bringing its total Series B round to more than $52 million — the largest among all quantum software companies, according to Pitchbook data.

Today’s round was led by Salesforce Ventures and saw participation from new investors including Alumni Ventures, ICM Allectus, Mindrock Capital, former General Dynamics Inc. partner Bill Lightfoot and global rugby legend and Australian business leader John Eales. Existing investors such as Airbus Ventures, Data Collective, Horizons, Main Sequence Ventures and Ridgeline Partners also joined in the round.

Q-CTRL is an Australian startup that’s hoping to tackle the problem of reliability in quantum computing. Rather than build quantum computers itself, it makes software that’s used to stabilize the quantum machines built by other companies.

Such software is necessary because existing quantum computers are incredibly fragile. Some of the best machines must be kept in isolated containers at temperatures close to absolute zero to maintain the stability of their “qubits,” the quantum equivalent of traditional bits. But even at these low temperatures, such systems can only run for short periods before errors begin creeping into their calculations.

Q-CTRL’s software is designed to help quantum computers stabilize these qubits, which can represent a zero or a one, or be both at the same time — the unique quality that makes them vastly more powerful than classical computers. The software works by visualizing qubit processing errors in a sleek dashboard that also provides insights into the cause. It provides tools that engineers can use to reprogram their quantum computer’s circuitry in order to correct those errors, making those machines far more capable. Demonstrations have shown that Q-CTRL’s software can improve the performance of quantum algorithms executed by qubits by up to 25 times.

The other advantage of Q-CTRL’s software is that it can be applied to a technique known as quantum sensing, which relies on the fragility of quantum hardware to take extremely sensitive measurements that are imperceptible to traditional sensors. The technology is based on trapped atoms and can be used to take precise measurements of underground water sources, or monitor space weather conditions, or navigate anywhere on Earth without the need for a global positioning system.

Quantum sensing provides big advantages over traditional sensors in terms of sensitivity and stability. Of course, the technology is still vulnerable to the same fragility as quantum computers are, but once again Q-CTRL’s software can manage this.

Salesforce Ventures Managing Director Robert Keith said the technology is “head-and-shoulders” above the rest of the industry when it comes to tackling the most foundational challenges in quantum computing. “Q-CTRL’s products are essential for enterprise adoption of quantum computing, and their use of AI is delivering critical insights across hardware platforms that no one else can match,” he said. “With their additional leadership in pioneering quantum sensors, we came to see Q-CTRL as one of the most consequential businesses in the sector for their ability to deliver value through quantum technology.”

Q-CTRL’s emphasis on expanding the performance and utility of existing quantum computers without the need for heavy investments was also recognized by International Data Corp. Research Manager Heather West in a recent report.

“Q-CTRL’s frictionless quantum infrastructure software has a shallow learning curve and allows CIOs and CTOs to become quantum ready today reducing enterprise risk,” West said. “Q-CTRL anticipates that with its software, enterprises will be able to leverage the skills of their current IT developers to easily develop, optimize, and execute quantum algorithms, and obtain high levels of performance on any given hardware at a low net cost.”

Q-CTRL claims more than 8,000 users of its product portfolio and says it achieved $15 million in bookings across its quantum computing and quantum sensing divisions in the last year. Those customers include the French multinational information technology services and consulting firm Capgemini SE, which said its work with Q-CTRL led it to discover new opportunities for quantum computing that were previously thought to be impossible.

“In the years ahead, as we move closer to quantum advantage, Q-CTRL’s products will enable real applications to deliver value sooner,” said Capgemini’s Quantum Lab Head and Chief Technology Information Officer Julian van Velzen.

Q-CTRL said it will use the funds from today’s round to double down on its product engineering and invest in its sales and marketing capabilities. The company has plans to grow its team from about 80 staff to 120 by the end of the year, at its offices in Sydney, Los Angeles and Berlin.

“Today’s additional validation from the investor community — especially while capital raises have been difficult to assemble — is a huge boost for our mission and ambition to truly make quantum technology useful,” said Q-CTRL Chief Executive Michael Biercuk.

Image: Q-CTRL