Active noise cancelation in superconducting Qubits using closed-loop feedback

A closed-loop feedback system for maintaining a desired operating frequency of a qubit, the system comprising:

• a readout resonator that is capacitively coupled to the qubit, the readout resonator configured to produce a series of measurements of the operating frequency of the qubit;
• a frequency estimator configured to receive the series of measurements and responsively produce an estimate of an offset between a measured operating frequency of the qubit and the desired operating frequency of the qubit;
• an accumulator configured to receive the estimate of the offset and responsively produce an accumulated error signal;
• an arbitrary waveform generator configured to receive the accumulated error signal and responsively generate a current;
• and
• an inductor that is inductively coupled to the qubit, the inductor receiving the generated current and responsively producing a magnetic flux, thereby actively controlling the operating frequency of the qubit.