Breakthrough: Real-Time Tracking of Qubit Fluctuations Unlocks Stable Quantum Computing

Scientists at the Niels Bohr Institute in Copenhagen have achieved a major advance in quantum computing by creating a real-time monitoring system for superconducting qubits. Led by postdoctoral researcher Dr. Fabrizio Berritta, the team developed an adaptive measurement approach using fast FPGA-based control hardware. This setup tracks fluctuations in a qubit's energy loss rate—known as relaxation—within milliseconds, matching the speed of the changes themselves. Previously, detection methods lagged by seconds or minutes, missing critical dynamics.

The innovation integrates commercially available FPGA processors with a Bayesian model that updates after every qubit measurement, enabling the controller to instantly classify qubits as 'good' or 'bad.' Collaborating with institutions like Chalmers University, Norwegian University of Science and Technology, and Leiden University, the researchers demonstrated detection roughly 100 times faster than prior techniques. This reveals rapid shifts in qubit performance that were previously invisible, providing new insights into their instability.

This matters because qubit fluctuations are a primary barrier to building practical quantum computers. By exposing these fast-changing behaviors, the system allows for quicker identification of faulty qubits and faster data collection on errors—reducing analysis time from days to seconds. It redefines timelines for qubit calibration and characterization, essential for scaling processors to useful sizes amid current material limitations.

Looking ahead, the Niels Bohr Institute plans to advance real-time calibration techniques. While the physics behind many fluctuations remains unexplained, this work highlights the power of industry-research partnerships and innovative hardware use, bringing fault-tolerant quantum computing closer to reality.