University of Copenhagen's Breakthrough: Real-Time Tracking of Qubit Fluctuations 100x Faster

Researchers at the University of Copenhagen's Niels Bohr Institute have achieved a major leap in quantum computing with a real-time monitoring system that tracks qubit fluctuations at unprecedented speeds. Led by postdoctoral researcher Dr. Fabrizio Berritta, the team used fast Field Programmable Gate Array (FPGA) hardware to detect changes in a qubit's energy loss rate within milliseconds—roughly 100 times faster than previous methods. By running adaptive Bayesian models directly on a commercial Quantum Machines OPX1000 controller, the system eliminates slow data transfers to conventional computers, keeping pace with the natural speed of qubit instability.

This breakthrough matters because qubits, the core units of quantum computers, can shift from stable ('good') to unstable ('bad') in fractions of a second due to environmental factors, undermining processor reliability. Prior techniques lagged behind by seconds or minutes, making it impossible to observe these dynamics in real time. Now, the FPGA setup provides instant insights, gathers statistics on faulty qubits in seconds instead of days, and reveals the true speed of fluctuations in superconducting qubits—knowledge that was previously inaccessible.

The innovation stems from close collaboration between the Niels Bohr Institute, Chalmers University (which fabricated the quantum hardware), and partners like the Norwegian University of Science and Technology and Leiden University. Associate Professor Morten Kjaergaard highlighted the controller's tight integration of logic, measurements, and feedback as key to success.

Looking ahead, this paves the way for real-time calibration and stabilization of quantum processors, essential for scaling to practical sizes. While unexplained fluctuations remain a challenge, the team's work—published in Physical Review X—signals a shift toward hybrid quantum-classical systems that could accelerate commercial quantum computing.