Singularity-free quantum tracking control of molecular rotor orientation

TL;DR

This paper develops a method to design singularity-free control fields for steering the orientation of a planar molecular rotor along desired paths, avoiding common issues in quantum tracking control.

Contribution

The authors derive singularity-free tracking expressions for controlling molecular rotor orientation, enabling smooth and reliable quantum control in molecular systems.

Findings

Successfully derived singularity-free control fields.

Simulated rotor orientation along specified trajectories.

Demonstrated practical control with two electric fields.

Abstract

Quantum tracking control aims to identify applied fields to steer the expectation values of particular observables along desired paths in time. The associated temporal fields can be identified by inverting the underlying dynamical equations for the observables. However, fields found in this manner are often plagued by undesirable singularities. In this paper we consider a planar molecular rotor, and derive singularity-free tracking expressions for the fields that steer the expectation of the orientation of the rotor along desired trajectories in time. Simulations are presented that utilize two orthogonal control electric fields to drive the orientation of the rotor along a series of designated tracks.