Approximation of reachable sets for coherently controlled open quantum systems: Application to quantum state engineering

作者：Li, Jun; Lu, Dawei; Luo, Zhihuang; Laflamme, Raymond; Peng, Xinhua^*; Du, Jiangfeng

来源：Physical Review A, 2016, 94(1): 012312.

DOI：10.1103/PhysRevA.94.012312

• NUCLEAR-MAGNETIC-RESONANCE
• SPIN DYNAMICS
• STEADY-STATE
• PURE STATES
• COMPUTATION
• SPECTROSCOPY
• DISSIPATION
• DRIVEN

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.

• 出版日期2016-7-7
• 单位北京计算科学研究中心; 中国科学技术大学