固态量子计算中动力学解耦方法抑制退相干的实验研究

发布时间：2018-12-05 20:49

【摘要】：为了能够在未来科学技术,比如量子计算中,利用固态体系电子自旋的量子相干特性,一个首要的任务就是克服环境导致的退相干。在目前众多理论方法中,动力学解耦方法通过不断的翻转电子自旋从而有效的平均掉电子自旋与环境之间的耦合,达到抑制退相干的目的。除此之外,考虑到它可以与其它应用相结合,比如与逻辑门操作,动力学解耦方法因此是一个很有前景并亟待实验研究的方向。在这篇博士论文中我们实验研究了动力学解耦方法在固态体系中抑制退相干的效果。首先,我们利用脉冲式电子顺磁共振技术在辐照丙二酸单晶样品中实验实现了Uhrig动力学解耦方案,延长了电子自旋的量子相干时间。并通过与理论方法相结合,我们定量的分析了固态体系中引起电子自旋退相干的物理机制。在此之后,我们将动力学解耦方法扩展到两比特体系,利用它实验实现了磷硅体系中量子纠缠的保持。紧接着,我们更进一步将动力学解耦方法应用到单电子自旋的金刚石色心体系中的相位精密测量实验方案中,提高了相位的探测精度。最后,我们在理论上给出了一种将动力学解耦方法与逻辑门操作相结合的方法,通过这种方法我们可以实现鲁棒性的两比特逻辑门操作。考虑到这种方法的局限性,我们还探讨了除了动力学解耦方法之外其他可以用来实现任意鲁棒性操作的实验方法。
[Abstract]:In order to make use of the quantum coherence properties of electron spin in the future science and technology, such as quantum computation, one of the most important tasks is to overcome the environment induced decoherence. Among the current theoretical methods, the dynamic decoupling method can effectively reverse the coupling between the average electron spin and the environment by constantly flipping the electron spin, so as to suppress the decoherence. In addition, considering that it can be combined with other applications, such as logic gate operation, dynamic decoupling is a promising and urgent research direction. In this doctoral thesis, we have experimentally studied the effect of the kinetic decoupling method on the suppression of decoherence in solid state systems. Firstly, we use pulse electron paramagnetic resonance (EPR) technique to realize the Uhrig kinetic decoupling scheme in irradiated malonic acid single crystal samples, which prolongs the quantum coherent time of electron spin. The physical mechanism of electron spin decoherence in solid state system is quantitatively analyzed by combining with theoretical method. After that, we extend the kinetic decoupling method to two-bit system, and use it to realize the quantum entanglement retention in phosphorus-silicon system. Then, we further apply the dynamic decoupling method to the phase precision measurement scheme of single electron spin diamond color center system, which improves the precision of phase detection. Finally, we give a method to combine the dynamic decoupling method with the logic gate operation in theory, by which we can realize the robust two-bit logic gate operation. Considering the limitations of this method, we also discuss other experimental methods which can be used to implement arbitrary robust operations in addition to the dynamic decoupling method.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：O413;TP38

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