Sun Guozhu, Wen Xueda, Gong Ming, Zhang Dan-Wei, Yu Yang, Zhu Shi-Liang, Chen Jian, Wu Peiheng, Han Siyuan
1] National Laboratory of Solid State Microstructures and Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China [2] Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China [3] Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045, USA.
Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Sci Rep. 2015 Feb 16;5:8463. doi: 10.1038/srep08463.
Landau-Zener transition (LZT) has been explored in a variety of physical systems for coherent population transfer between different quantum states. In recent years, there have been various proposals for applying LZT to quantum information processing because when compared to the methods using ac pulse for coherent population transfer, protocols based on LZT are less sensitive to timing errors. However, the effect of finite range of qubit energy available to LZT based state control operations has not been thoroughly examined. In this work, we show that using the well-known Landau-Zener formula in the vicinity of an avoided energy-level crossing will cause considerable errors due to coherent oscillation of the transition probability in a single-passage LZT experiment. The data agree well with the numerical simulations which take the transient dynamics of LZT into account. These results not only provide a closer view on the issue of finite-time LZT but also shed light on its effects on the quantum state manipulation.
兰道-齐纳跃迁（LZT）已在各种物理系统中得到研究，用于不同量子态之间的相干布居转移。近年来，有各种将LZT应用于量子信息处理的提议，因为与使用交流脉冲进行相干布居转移的方法相比，基于LZT的协议对定时误差不太敏感。然而，基于LZT的状态控制操作可用的量子比特能量有限范围的影响尚未得到彻底研究。在这项工作中，我们表明，在避免能级交叉附近使用著名的兰道-齐纳公式会由于单通道LZT实验中跃迁概率的相干振荡而导致相当大的误差。数据与考虑了LZT瞬态动力学的数值模拟结果吻合良好。这些结果不仅更深入地揭示了有限时间LZT问题，还阐明了其对量子态操纵的影响。
