Feedback Control of Rabi Oscillations in Circuit QED

TL;DR

This paper presents a feedback control method using Lyapunov techniques to stabilize Rabi oscillations in a superconducting qubit within circuit QED, enhancing coherence through real-time measurement and control.

Contribution

It introduces a novel feedback control scheme based on Lyapunov functions for stabilizing Rabi oscillations in superconducting qubits.

Findings

Effective stabilization of Rabi oscillations demonstrated in simulations.

Enhanced signal-to-noise ratio achieved through time-delayed reference extraction.

The control law improves coherence and stability of qubit oscillations.

Abstract

We consider the feedback stabilization of Rabi oscillations in a superconducting qubit which is coupled to a microwave readout cavity. The signal is readout by homodyne detection of the in-phase quadrature amplitude of the weak measurement output. By multiplying the time-delayed Rabi reference, one can extract the signal, with maximum signal-to-noise ratio, from the noise. We further track and stabilize the Rabi oscillations by using Lyapunov feedback control to properly adjust the input Rabi drives. Theoretical and simulation results illustrate the effectiveness of the proposed control law.