朗道齐纳转变在超导量子比特中的应用

发布时间：2018-01-03 14:37

  本文关键词：朗道齐纳转变在超导量子比特中的应用　出处：《南京大学》2016年博士论文　论文类型：学位论文

  更多相关文章： 量子计算 超导量子比特 朗道齐纳转变 基布尔楚雷克力学 朗道齐纳斯特伯格干涉 量子随机共振 快速绝热过程

【摘要】：量子计算和量子信息是利用量子力学系统进行信息研究的新兴热点。超导量子比特由于其易操作性和强拓展性,正成为目前实现量子计算的最可能的途径。对于量子比特状态的操作的研究,以及利用量子比特进行量子模拟,是量子计算研究的核心之一。朗道齐纳转变是一种熟知的量子能级转变的理论,而其在超导量子计算中应用尚未被完全发掘。本文在以下几个方面对于量子比特的性质以及朗道齐纳转变在量子计算中的应用进行了展现。在基本的量子比特参数的确定上,我们展示了量子比特能级的确定、退相干时间的测量、拉比震荡、与天然二能级的耦合等方面的实验方法和拓展研究,系统研究了单量子比特的性质及操作方法。在利用量子比特进行量子模拟方面,我们根据基布尔楚雷克力学与朗道齐纳转变相关性的预言,使用朗道齐纳转变来模拟和研究基布尔楚雷克力学。在三维传输子量子比特中,我们观察到了朗道齐纳转变中的绝热.脉冲近似,量子态冻结,以及一维伊辛模型中的标度律等现象,验证了基布尔楚雷克力学与朗道齐纳理论之间的关联。此外,我们研究了强退相干作用下的朗道齐纳转变,并开创性的利用能隙重调的方法研究不同退相干影响下的朗道齐纳转变行为。在三维传输子比特中,我们利用微波形成有效的微波修饰态来与量子比特系统的基态和第一激发态构成有效的免交叉结构,并且利用了微波调频的快速可调性质,首次在超导三维传输子量子比特中观察到了朗道齐纳斯特伯格干涉现象。此外,凭借时间精度为1纳秒的时域测量方法,我们进行了在朗道齐纳斯特伯格干涉过程中的时间演化的测量,观察到了量子比特状态在干涉过程中的时域演化过程。在量子比特状态的操纵方面,利用波形调制的朗道齐纳转变,我们展示了一种有效的进行量子态的转移和操作的实用的调频快速绝热过程。这种方法可以有效的实现不同能级量子态之间的转移。相比较于通常的利用共振拉比震荡的方法,这种方法对操作时间是否精确,对频率是否共振,以及对功率参数都不敏感,具有非常高的鲁棒性。我们比较了不同波形调制下的快速绝热过程的鲁棒性和误差率,展示了特定波形调制的快速绝热过程的有效性和可操作性。此外,针对快速绝热过程是否为有效门操作的疑问,我们研究了调频快速绝热过程针对不同目标门操作的保真度,验证了其在特定参数条件下可以成为一种有效量子逻辑门操作的应用前景。
[Abstract]:Quantum computation and quantum information is a new hotspot of information research using quantum mechanical systems. The superconducting qubit due to its easy operation and strong expansibility, is becoming the most possible way is to realize quantum computation. Research on quantum bit state of operation, and then simulated by quantum qubit, is one of the core computing study on the quantum Landau Zener transformation is a transformation known as quantum level theory, and its application in superconducting quantum computing has not yet been fully explored. This paper in the following aspects for properties of quantum bit and Landau Zener change the application in quantum computation for the show. In determining the basic parameters of the quantum bit we show, determine the quantum bit level, back measurement, coherent time Rabi oscillation experiment method and natural, and other aspects of the two level of the coupling and extension Study on the properties of the system, and the operation method of single qubit quantum simulation. In the use of quantum bits, we according to Keble Zurek mechanics and Landau Zener transition correlation predictions, using the Landau Zener transition to simulate and study Chulei chocolate. Keble in three transmission sub qubits, we observed adiabatic Landau Zener transition. The impulse approximation, the quantum state of freezing, and one dimensional Ising model scaling phenomenon, verified the relationship between kibble Zurek mechanics and Landau Zener theory. Furthermore, we study the strong decoherence change under the influence of Landau Zener, and groundbreaking use of gap reset different decoherence Landau Zener transition behavior under the influence. In the three-dimensional transmission sub bit, we use microwave microwave modified state effectively with quantum bit system The ground state and the first excited state constitutes free cross structure effectively, and the use of microwave frequency fast tunable properties were observed for the first time Landau Qi Berg Nast interference phenomenon in the superconducting quantum bits in a three-dimensional transmission. In addition, with the accuracy of 1 nanosecond time domain measurement method, we conducted interference measurement evolution process in the time when Landau Berg observed Qi Nast, quantum bit state interference in time domain evolution process. In the manipulation of quantum bit state transition, using waveform modulation Landau Zener, we show an effective transfer and operation of the quantum state of practical FM rapid adiabatic process. This the method can realize the transfer between different levels of quantum states effectively. Compared to the method usually use resonance Rabi oscillation, this method of operation time is fine Indeed, the frequency and power parameters of resonance, are not sensitive, has very high robustness. We compare the robustness and error of rapid adiabatic process under different waveform modulation rate, showing the rapid adiabatic process specific waveform modulation of the effectiveness and operability. In addition, the rapid adiabatic process for the effective operation of doubt, we study the adiabatic process for different target FM fast door operation fidelity, to verify its application prospect can become a kind of effective quantum logic gate operation under certain parameter conditions.

【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O413
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本文编号：1374334