Approximation of Reachable Set for Coherently Controlled Open Quantum Systems: Application to Quantum State Engineering

TL;DR

This paper develops methods to approximately compute the reachable states of open quantum systems under coherent control, aiding in quantum state engineering and demonstrating near-optimal control in NMR systems.

Contribution

It introduces novel techniques for approximating reachable sets in dissipative quantum systems, enhancing control assessment and application to quantum state preparation.

Findings

Successfully applied to a two-qubit NMR system

Achieved near-optimal control performance in purity tasks

Demonstrated environment-assisted quantum dynamics benefits

Abstract

Precisely characterizing and controlling realistic open quantum systems is one of the most challenging and exciting frontiers in quantum sciences and technologies. In this Letter, we present methods of approximately computing reachable sets for coherently controlled dissipative systems, which is very useful for assessing control performances. We apply this to a two-qubit nuclear magnetic resonance spin system and implement some tasks of quantum control in open systems at a near optimal performance in view of purity: e.g., increasing polarization and preparing pseudo-pure states. Our work shows interesting and promising applications of environment-assisted quantum dynamics.