【摘要】：量子計(jì)算理論向我們展示了誘人的前景,然而要真正實(shí)現(xiàn)有實(shí)用價(jià)值量子計(jì)算機(jī),我們?nèi)杂幸恍l件沒(méi)有達(dá)到,目前的實(shí)驗(yàn)技術(shù)條件制備的量子比特往往還不能同時(shí)具有良好的相干性和集成性。另外,還有一個(gè)重要的問(wèn)題需要我們更深一步探索,那就是,當(dāng)我們把很多量子比特集成在一起的時(shí)候,如何可以更好的進(jìn)行量子計(jì)算。本文主要介紹了我們?cè)诙囿w系統(tǒng)中關(guān)于量子計(jì)算、調(diào)控與量子關(guān)聯(lián)三個(gè)方面的研究工作,主要包括： (1)我們提出了一個(gè)用超導(dǎo)Josephson結(jié)量子比特實(shí)現(xiàn)一個(gè)自包含的量子制冷機(jī)的方案。這個(gè)制冷機(jī)系統(tǒng)中包含三個(gè)量子比特,分別充當(dāng)待降溫目標(biāo)、制冷機(jī)和熱機(jī)的角色。通過(guò)調(diào)節(jié)適當(dāng)?shù)墓舱駰l件,這三個(gè)量子比特可以從直接的兩體作用產(chǎn)生等效的三體相互作用。另外,通過(guò)向這三個(gè)量子比特輸入不同強(qiáng)度的電流噪聲,我們可以為它們提供不同的等效溫度,從而不需要其他外加調(diào)控就可以使這個(gè)制冷機(jī)系統(tǒng)得以持續(xù)工作。 (2)我們演示了在一個(gè)由Josephson磁通量子比特搭建成的陣列上用隧穿的方法進(jìn)行量子計(jì)算的過(guò)程。這個(gè)是一個(gè)具有拓?fù)湫虻南到y(tǒng),它基態(tài)空間的簡(jiǎn)并度與陣列上穿孔的數(shù)量有關(guān),即與陣列的拓?fù)溆嘘P(guān)。我們演示了如何在這個(gè)簡(jiǎn)并空間中對(duì)邏輯量子比特進(jìn)行編碼,并通過(guò)施加適當(dāng)?shù)耐鈭?chǎng),驅(qū)動(dòng)準(zhǔn)粒子沿特定的非平庸路徑運(yùn)動(dòng),從而完成對(duì)邏輯量子比特的操作。原則上,在這個(gè)系統(tǒng)上可以進(jìn)行通用的量子計(jì)算。 (3)我們研究了在拓?fù)湎嘧兿到y(tǒng)中的量子關(guān)聯(lián),包括一維的和二維的系統(tǒng)。我們發(fā)現(xiàn),在二維的拓?fù)湎嘧兿到y(tǒng)中,局域的量子關(guān)聯(lián)會(huì)完全消除,而一維系統(tǒng)中的局域量子關(guān)聯(lián)則一直保持非零,但也是被強(qiáng)烈的壓制的,這說(shuō)明拓?fù)湫蛳到y(tǒng)的量子關(guān)聯(lián)主要存在于整體上。我們認(rèn)為這種性質(zhì)是由拓?fù)湎嘞到y(tǒng)中的局域變換對(duì)稱性帶來(lái)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.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2012
【分類號(hào)】：O413;TP38

【引證文獻(xiàn)】

相關(guān)博士學(xué)位論文 前1條

1 唐世清;原子—光子系統(tǒng)的合作效應(yīng)和相干控制[D];湖南師范大學(xué);2015年

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本文編號(hào)：2507423