Hybrid Predictive Quantum Feedback: Extending Qubit Lifetimes Beyond the Wiseman–Milburn Limit

Amplitude damping sets a fundamental limit on qubit lifetimes, while standard Wiseman-Milburn (W-M) feedback offers limited improvement due to (i) single-quadrature homodyne readout and (ii) unavoidable loop latency. We propose a hybrid architecture that combines (a) an ancilla-assisted coherent feedback pathway that effectively recovers information from both field quadratures and (b) a lightweight supervised predictor that forecasts the delayed homodyne current to phase-align actuation. We derive compact effective decay-rate models for classical W-M, ancilla-assisted, and predictive (ancilla+ML) feedback, and benchmark them with numerical simulations under realistic superconducting-qubit parameters. The hybrid loop surpasses the W-M bound, yielding multi-fold extension of the effective