Jelmer Renema uses quantum properties of light for superfast information processing
Jelmer Renema is working on the development of photonic quantum computers. In such systems, individual light particles, photons, perform calculations that are far more complex than is currently possible with ordinary (super) computers. He obtained his PhD in Leiden in 2015 quantum optics and set off to a postdoc position at Oxford. It was there that he first worked on optical chips to perform calculations with light. During his stay in Oxford, his research group faced a problem: there were not enough optical chips for their research.
“I discussed the problem with colleagues, including Tom Wolterink, a postdoc who had just obtained his PhD in Twente. He referred us to the work of Klaus Boller’s Laser Physics and Nonlinear Optics group at the University of Twente,” Renema says. “It turned out that the chip they had designed for 5G technology was also very suitable for processing quantum light.”
After completing his postdoc, Renema was able to continue working with the chips on a Veni grant in Twente. At the start of his appointment in 2018, he not only unfolded his scientific plans, but also held a pitch on the commercial possibilities he saw for a quantum processor. A new startup, Quix Quantum, soon emerged in collaboration with LioniX.
“We are now the market leader in photonic hardware for quantum computers. We make a universal chip that is fully programmable. Thus one can perform every conceivable quantum optical experiment with it,” says Renema, who praises the infrastructure in Twente. “There is a whole cluster of companies around the University of Twente that are doing great things. Communication lines are short so you can act quickly. Moreover, we have the facilities to do excellent scientific quantum experiments with the chips.”
Renema’s academic research has both an applied and a fundamental character. He explains: “We investigate the conditions for a quantum computer based on photonics to actually offer advantages for complicated calculations, and we try to find out when it may not be the most convenient method. We also look at the quantum properties of light in a fundamental manner. For example, we investigate the seemingly incompatibility of the physical laws in quantum systems and the laws of thermodynamics that apply in the world around us. With our quantum processor, we can approach these kinds of problems not only theoretically, but also experimentally.”
Renema's academic work brought him into contact with the team of Chinese researchers that showed that a quantum computer based on photonics has ‘quantum advantage’ in 2021. Quantum advantage means that the computer can solve problems that are too complex for an ordinary supercomputer. Renema contributed to the theoretical underpinnings.
“The fact that we use photons as quantum units for calculations has advantages over the superconducting qubits that many other quantum computers are based on,” he says. “This research shows that we can achieve quantum advantage with photonics much earlier than foreseen in the Dutch roadmap for quantum technology.”
As an assistant professor, Renema is no longer working in the lab himself. He is pleased with a capable team of PhD students and researchers to carry out the research and supervise the bachelor’s and master’s students. He does, however, teach the popular Quantum Information course in the master’s phase. Renema knows from experience what the influence of a teacher can be. He chose to study physics thanks to two enthusiastic secondary school teachers. “One of them let me participate in the Physics Olympiad where I got all kinds of extra lessons outside the normal curriculum,” he says. “One Friday afternoon, the other one decided to derive the equation for a pendulum for us. He was hopelessly stuck at first because of a misplaced minus sign, and then he was so happy when he finally found the solution. These teachers showed me that physics was more than what you learn in school and that it was worth getting involved in. Even now, I always try to tell students that science is also about human interaction. As a researcher you are part of a community and you learn to take ownership by not being afraid to approach others with your ideas.”
Jelmer Renema studied physics in Leiden, where he also obtained his PhD in 2015 (cum laude) on a detection mechanism for superconducting single photon detectors. He received a Rubicon grant from NWO for his postdoc period in Oxford, where he became acquainted with the research in Twente. In 2018 he received a Veni grant for a postdoc position at the University of Twente and started as an associate professor at the Adaptive Quantum Optics group in 2020. In addition to his academic work, Renema is CTO of the successful UT start-up Quix Quantum.
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