Unnati Akhouri is a Product Solutions Physicist at Quantum Machines with a PhD from Penn State and an Oxford Master’s, specializing in open quantum systems and qubit decoherence. She is the creator of the “Bit, Byte, and Nibble” series and “Fatal Physics” comics, aimed at explaining quantum physics and general relativity concepts.
Presentation Title:
Fast-Feedback Qubit Calibration Interleaved with Quantum Circuits
Presentation Abstract:
Quantum computers will require thousands to millions of qubits with precisely calibrated state-preparation, gate, and measurement operations. Yet the underlying control parameters, including the pulse amplitudes, frequencies, and qubit coherence properties, fluctuate on timescales as short as milliseconds. Conventional calibration routines estimate these parameters in slow, sequential batches that demand system downtime, such that by the time corrections are applied, the qubit has already drifted away from the calibrated estimate. Closed-loop calibration that updates parameters faster than they fluctuate is therefore essential. Here we implement fast-feedback calibration protocols on a quantum controller, applying measurement outcomes to update gate parameters in situ within gate-level programs. In this approach hybrid control embeds classical computation in the pulse processing unit of the OPX1000, executing operations such as Bayesian estimation and parameter tracking at microsecond latency. Extended through the Open Acceleration Stack, the presented architecture offloads readout, decoding, and algorithmic computation to CPUs and GPUs while preserving deterministic real-time timing.