A new ultra-fast monitoring system at the Niels Bohr Institute enables real-time tracking of rapid fluctuations in superconducting qubits’ energy-loss rates within milliseconds, revealing dynamics that were previously unseen.

The team integrated a commercially available FPGA-based controller from Quantum Machines and designed the quantum processing unit at Chalmers University, illustrating accessible hardware integration for real-time quantum control.

By combining FPGA hardware with adaptive Bayesian measurement, researchers update the qubit relaxation rate estimate after each measurement, allowing the readout to keep pace with environmental fluctuations.

The findings indicate that real-time monitoring and calibration are essential for scalable quantum processors, highlighting that system performance is often limited by the worst qubits rather than the best and stressing rapid error detection and correction.

The project brought together institutions including the Niels Bohr Institute, Novo Nordisk Foundation Quantum Computing Programme, Norwegian University of Science and Technology, Leiden University, and Chalmers University, led by postdoctoral researcher Dr. Fabrizio Berritta.

The method continuously updates a Bayesian model of qubit behavior after each measurement, enabling near real-time identification of which qubits perform well or poorly and collecting statistics on troublesome qubits within seconds.

Using an FPGA-based OPX1000 controller, the approach performs rapid processing and feedforward without slow data transfers to a traditional computer, achieving about a hundredfold speed increase over prior methods.

Experiments not only demonstrated faster tracking but also quantified the previously unknown timescale of fluctuations in superconducting qubits, offering new insights into stability and calibration needs.