An FPGA-based quantum feedback system for real-time qubit control

Measurement-based quantum feedback is highly sought after due to its potential for quantum error correction and preserving quantum coherence. However, measurement-based quantum feedback has been difficult to achieve due to the limited lifetime of qubits as compared to the longer time required for readout and feedback signal processing. We present a new FPGA-based qubit control architecture that integrates the qubit readout, state recognition, and feedback response together to minimize latency. Using our initial hardware, we demonstrate real-time quantum feedback on superconducting qubits and apply this technology to a multi-qubit superconducting quantum processor.