Pulse Width Modulation for Speeding Up Quantum Optimal Control Design

TL;DR

This paper introduces a PWM-based gradient descent method to accelerate quantum optimal control design, demonstrating improved efficiency and smooth control implementation for complex quantum systems.

Contribution

It combines PWM with gradient descent for faster quantum control optimization and proposes smooth control realization for experimental applicability.

Findings

Enhanced computational efficiency over traditional methods

Successful application to 3-qubit and 6-qubit systems

Demonstrated advantages using experimental data from D-Norleucine

Abstract

This paper focuses on accelerating quantum optimal control design for complex quantum systems. Based on our previous work [{arXiv:1607.04054}], we combine Pulse Width Modulation (PWM) and gradient descent algorithm into solving quantum optimal control problems, which shows distinct improvement of computational efficiency in various cases. To further apply this algorithm to potential experiments, we also propose the smooth realization of the optimized control solution, e.g. using Gaussian pulse train to replace rectangular pulses. Based on the experimental data of the D-Norleucine molecule, we numerically find optimal control functions in $3$-qubit and $6$-qubit systems, and demonstrate its efficiency advantage compared with basic GRAPE algorithm.