Orthogonal measurement-assisted quantum control

TL;DR

This paper introduces globally efficient quantum control algorithms that utilize orthogonal measurements to reconstruct propagators, enabling direct paths in the control space and offering an experimental alternative to traditional adaptive learning methods.

Contribution

The paper presents novel quantum control algorithms based on orthogonal measurements that improve search efficiency and are experimentally implementable, contrasting with existing local gradient or heuristic methods.

Findings

Algorithms follow direct paths in control space

Performance surpasses local gradient-based methods

Suitable for experimental quantum control applications

Abstract

Existing algorithms for the optimal control of quantum observables are based on locally optimal steps in the space of control fields, or as in the case of genetic algorithms, operate on the basis of heuristics that do not explicitly take into account details pertaining to the geometry of the search space. We present globally efficient algorithms for quantum observable control that follow direct or close-to-direct paths in the domain of unitary dynamical propagators, based on partial reconstruction of these propagators at successive points along the search trajectory through orthogonal observable measurements. These algorithms can be implemented experimentally and offer an alternative to the adaptive learning control approach to optimal control experiments (OCE). Their performance is compared to that of local gradient-based control optimization.