Reachable set of open quantum dynamics for a single spin in Markovian environment

Haidong Yuan

Yong-Gan Zhao, Yi-Chong Ren, Hong-Yi Fan

Claudio Altafini

Haidong Yuan

In this article we study the reachable set of open single spin systems in Markovian environment by using coherent control. Given the initial state, we compute all the possible states to which the spin can be driven to at a given time. Such characterization of reachable set gives the physical limits of controlled evolution of quantum systems and provide optimal control strategies achieving these limits.

Carole Addis

Jun Li, Dawei Lu, Zhihuang Luo +3 more

Precisely characterizing and controlling realistic quantum systems under noises is a challenging frontier in quantum sciences and technologies. In developing reliable controls for open quantum systems, one is often confronted with the problem of the lack of knowledge on the system controllability. The purpose of this paper is to give a numerical approach to this problem, that is, to approximately compute the reachable set of states for coherently controlled quantum Markovian systems. The approximation consists of setting both upper and lower bounds for system's reachable region of states. Furthermore, we apply our reachability analysis to the control of the relaxation dynamics of a two-qubit nuclear magnetic resonance spin system. We implement some experimental tasks of quantum state engineering in this open system at a near optimal performance in view of purity: e.g., increasing polarization and preparing pseudopure states. These results demonstrate the usefulness of our theory and show interesting and promising applications of environment-assisted quantum dynamics.