物理科学与技术学院知识库

在本论文中，我们研究了开放量子系统中的量子比特的量子相干性冻结行为，分析了量子系统与其环境形成束缚态时对量子系统相干性的影响。我们研究了处于真空库场中量子比特的量子相干性的演化，研究结果表明当系统与环境形成束缚态，相干性会冻结，得到部分的保留，这种长时极限下相干性的冻结表明系统最后演化到一个非基态的稳定态并且退相干得到了抑制。这种相干性冻结的现象为我们提供了一种保留相干性的办法，这可以通库工程调节相关参数实现，比如介观势阱、冷原子以及光晶格材料。

This thesis is contributed to the study of the freeezing of quantum coherence of qubit influenced by an environment. We investigate the time evolution of the quantum coherence of the qubit and reveal the profound impact of the potential formation of a bound state between the qubit and its environment on the long-time behavior of quantum coherence of the qubit. It is found that if the bound state is formed, then the quantum coherence of the qubit would be partially frozen in the long time limit. It indicates that the steady state of the qubit is no longer its ground state but a mixed state and the decoherence of the qubit is suppressed. This phenomenon gives us a way to protect quantum coherence from decoherence. It could be achieved by modifying related parameters using of reservoir engineering technique, such as ion traps, cold atom BEC and photonic crystal materials.