多体系统中的量子计算、调控与量子关联
发布时间：2019-06-28 15:52
【摘要】：量子计算理论向我们展示了诱人的前景,然而要真正实现有实用价值量子计算机,我们仍有一些条件没有达到,目前的实验技术条件制备的量子比特往往还不能同时具有良好的相干性和集成性。另外,还有一个重要的问题需要我们更深一步探索,那就是,当我们把很多量子比特集成在一起的时候,如何可以更好的进行量子计算。本文主要介绍了我们在多体系统中关于量子计算、调控与量子关联三个方面的研究工作,主要包括： (1)我们提出了一个用超导Josephson结量子比特实现一个自包含的量子制冷机的方案。这个制冷机系统中包含三个量子比特,分别充当待降温目标、制冷机和热机的角色。通过调节适当的共振条件,这三个量子比特可以从直接的两体作用产生等效的三体相互作用。另外,通过向这三个量子比特输入不同强度的电流噪声,我们可以为它们提供不同的等效温度,从而不需要其他外加调控就可以使这个制冷机系统得以持续工作。 (2)我们演示了在一个由Josephson磁通量子比特搭建成的阵列上用隧穿的方法进行量子计算的过程。这个是一个具有拓扑序的系统,它基态空间的简并度与阵列上穿孔的数量有关,即与阵列的拓扑有关。我们演示了如何在这个简并空间中对逻辑量子比特进行编码,并通过施加适当的外场,驱动准粒子沿特定的非平庸路径运动,从而完成对逻辑量子比特的操作。原则上,在这个系统上可以进行通用的量子计算。 (3)我们研究了在拓扑相变系统中的量子关联,包括一维的和二维的系统。我们发现,在二维的拓扑相变系统中,局域的量子关联会完全消除,而一维系统中的局域量子关联则一直保持非零,但也是被强烈的压制的,这说明拓扑序系统的量子关联主要存在于整体上。我们认为这种性质是由拓扑相系统中的局域变换对称性带来的。
[Abstract]:Quantum computing theory shows us attractive prospects. However, in order to realize the practical value quantum computer, we still have some conditions that have not been achieved. The quantum bits prepared by the current experimental technical conditions often can not have good coherence and integration at the same time. In addition, there is an important question that needs to be explored further, that is, how to do quantum computing better when we integrate a lot of qubits together. In this paper, we mainly introduce our research work on quantum computing, regulation and quantum correlation in multi-body systems, including: (1) We propose a scheme to realize a self-contained quantum refrigerator using superconducting Josephson junction qubits. The refrigerator system consists of three qubits, which act as cooling targets, refrigerators and heat engines. By adjusting the appropriate resonance conditions, the three qubits can produce the equivalent three-body interaction from the direct two-body interaction. In addition, by inputting different intensities of current noise into the three qubits, we can provide them with different equivalent temperatures, so that the refrigerator system can continue to work without other external controls. (2) We demonstrate the process of quantum calculation by tunneling on an array built by Josephson flux quantum bit lap. This is a system with topological order. The degeneracy of the ground state space is related to the number of holes in the array, that is to say, to the topology of the array. We demonstrate how to code logical qubits in this degeneracy space and drive quasi-particles to move along a specific non-mediocre path by applying appropriate external fields, so as to complete the operation of logical qubits. In principle, general quantum computation can be carried out on this system. (3) We study the quantum correlation in topological phase transition systems, including one-dimensional and two-dimensional systems. We find that in the two-dimensional topological phase transition system, the local quantum correlation will be completely eliminated, while the local quantum correlation in the one-dimensional system will remain non-zero, but it is also strongly suppressed, which indicates that the quantum correlation of the topological order system mainly exists in the whole. We think that this property is caused by the local transformation symmetry in topological phase systems.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：O413;TP38
本文编号：2507423
[Abstract]:Quantum computing theory shows us attractive prospects. However, in order to realize the practical value quantum computer, we still have some conditions that have not been achieved. The quantum bits prepared by the current experimental technical conditions often can not have good coherence and integration at the same time. In addition, there is an important question that needs to be explored further, that is, how to do quantum computing better when we integrate a lot of qubits together. In this paper, we mainly introduce our research work on quantum computing, regulation and quantum correlation in multi-body systems, including: (1) We propose a scheme to realize a self-contained quantum refrigerator using superconducting Josephson junction qubits. The refrigerator system consists of three qubits, which act as cooling targets, refrigerators and heat engines. By adjusting the appropriate resonance conditions, the three qubits can produce the equivalent three-body interaction from the direct two-body interaction. In addition, by inputting different intensities of current noise into the three qubits, we can provide them with different equivalent temperatures, so that the refrigerator system can continue to work without other external controls. (2) We demonstrate the process of quantum calculation by tunneling on an array built by Josephson flux quantum bit lap. This is a system with topological order. The degeneracy of the ground state space is related to the number of holes in the array, that is to say, to the topology of the array. We demonstrate how to code logical qubits in this degeneracy space and drive quasi-particles to move along a specific non-mediocre path by applying appropriate external fields, so as to complete the operation of logical qubits. In principle, general quantum computation can be carried out on this system. (3) We study the quantum correlation in topological phase transition systems, including one-dimensional and two-dimensional systems. We find that in the two-dimensional topological phase transition system, the local quantum correlation will be completely eliminated, while the local quantum correlation in the one-dimensional system will remain non-zero, but it is also strongly suppressed, which indicates that the quantum correlation of the topological order system mainly exists in the whole. We think that this property is caused by the local transformation symmetry in topological phase systems.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：O413;TP38
【引证文献】
相关博士学位论文 前1条
1 唐世清;原子—光子系统的合作效应和相干控制[D];湖南师范大学;2015年
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