Quantum Optimal Control Theory

TL;DR

This paper introduces quantum optimal control theory (QOCT), explaining how to design laser pulses for controlling quantum dynamics, with algorithms applicable to simple systems and time-dependent targets.

Contribution

It provides a comprehensive tutorial on QOCT, detailing control equations, solution schemes, and methods to incorporate constraints, including time-dependent control targets.

Findings

Successful algorithms for solving control equations

Application to simple quantum systems

Handling of time-dependent control targets

Abstract

The control of quantum dynamics via specially tailored laser pulses is a long-standing goal in physics and chemistry. Partly, this dream has come true, as sophisticated pulse shaping experiments allow to coherently control product ratios of chemical reactions. The theoretical design of the laser pulse to transfer an initial state to a given final state can be achieved with the help of quantum optimal control theory (QOCT). This tutorial provides an introduction to QOCT. It shows how the control equations defining such an optimal pulse follow from the variation of a properly defined functional. We explain the most successful schemes to solve these control equations and show how to incorporate additional constraints in the pulse design. The algorithms are then applied to simple quantum systems and the obtained pulses are analyzed. Besides the traditional final-time control methods, the tutorial also presents an algorithm and an example to handle time-dependent control targets.