Efficient control pulses for continuous quantum gate families through coordinated re-optimization

TL;DR

This paper introduces a fast, efficient method for generating high-fidelity control pulses for continuous quantum gate families by optimizing reference pulses and interpolating between them, significantly reducing calibration time.

Contribution

The authors propose a novel re-optimization technique that produces reference pulses for continuous quantum gates, enabling instant high-fidelity interpolation and outperforming neural network approaches in efficiency.

Findings

Achieves high-fidelity control pulses for two-qubit gates via interpolation.

Reduces calibration time by 7.7 times compared to neural network methods.

Generalizes to any number of gate parameters and integrates with advanced optimization algorithms.

Abstract

We present a general method to quickly generate high-fidelity control pulses for any continuously-parameterized set of quantum gates after calibrating a small number of reference pulses. We find that interpolating between optimized control pulses for different quantum operations does not immediately yield a high-fidelity intermediate operation. To solve this problem, we propose a method to optimize control pulses specifically to provide good interpolations. We pick several reference operations in the gate family of interest and optimize pulses that implement these operations, then iteratively re-optimize the pulses to guide their shapes to be similar for operations that are closely related. Once this set of reference pulses is calibrated, we can use a straightforward linear interpolation method to instantly obtain high-fidelity pulses for arbitrary gates in the continuous operation space. We demonstrate this procedure on the three-parameter Cartan decomposition of two-qubit gates to obtain control pulses for any arbitrary two-qubit gate (up to single-qubit operations) with consistently high fidelity. Compared to previous neural network approaches, the method is 7.7x more computationally efficient to calibrate the pulse space for the set of all single-qubit gates. Our technique generalizes to any number of gate parameters and could easily be used with advanced pulse optimization algorithms to allow for better translation from simulation to experiment.