推薦論文摘要

推薦論文摘要

Grover算法量子處理架構(gòu)的設(shè)計(jì)與模擬

張洪濤，代永濤，凃玲英

針對(duì)混合架構(gòu)經(jīng)典-量子算法的量子算法處理單

元，設(shè)計(jì)基于 Grover算法的量子處理架構(gòu)。將一種用

于量子計(jì)算仿真的量子程序設(shè)計(jì)語(yǔ)言引入 Grover量子

搜索算法中，并在Linux操作系統(tǒng)中進(jìn)行執(zhí)行與模擬。結(jié)果表明：所提架構(gòu)可以提高量子搜索算法的執(zhí)行性

能；利用反饋調(diào)節(jié)可以有效地實(shí)現(xiàn)量子搜索算法的最佳

性能。

Grover量子搜索算法；量子處理架構(gòu)；量子程

序設(shè)計(jì)語(yǔ)言；仿真

來(lái)源出版物：華僑大學(xué)學(xué)報(bào)（自然科學(xué)版）, 2016, 37(6): 749-753

聯(lián)系郵箱：張洪濤，zhanght@mail.hbut.edu.cn

量子計(jì)算復(fù)雜性理論綜述

張煥國(guó)，毛少武，吳萬(wàn)青，等

摘要：量子計(jì)算復(fù)雜性理論是量子計(jì)算機(jī)科學(xué)的基礎(chǔ)理論之一，對(duì)量子環(huán)境下的算法設(shè)計(jì)和問(wèn)題求解具有指導(dǎo)意義。因此，該文對(duì)量子計(jì)算復(fù)雜性理論進(jìn)行了綜述。首先，介紹了各種量子圖靈機(jī)模型及它們之間的關(guān)系。其次，量子計(jì)算復(fù)雜性是指在量子環(huán)境下對(duì)于某個(gè)問(wèn)題求解的困難程度，包含問(wèn)題復(fù)雜性、算法復(fù)雜性等。于是，該文介紹了量子問(wèn)題復(fù)雜性、量子線路復(fù)雜性、量子算法復(fù)雜性，并且介紹了量子基本運(yùn)算和 Shor算法的優(yōu)化實(shí)現(xiàn)。第三，格被看做是一種具有周期性結(jié)構(gòu)的n維點(diǎn)空間集合。格密碼有很多優(yōu)勢(shì)，包括具有抗量子計(jì)算的潛力，格算法具有簡(jiǎn)單易實(shí)現(xiàn)、高效性、可并行性特點(diǎn)，格密碼已經(jīng)被證明在最壞條件下和平均條件下具有同等的安全性。因此該文介紹了格的困難問(wèn)題，以及主要的格密碼方案現(xiàn)狀。最后，對(duì)今后值得研究的一些重要問(wèn)題和量子計(jì)算環(huán)境下的密碼設(shè)計(jì)與分析給出了展望。

關(guān)鍵詞：量子計(jì)算；量子圖靈機(jī)；量子計(jì)算復(fù)雜性；量子線路；量子環(huán)境下的密碼

來(lái)源出版物：計(jì)算機(jī)學(xué)報(bào), 2016,39(12), 2403-2428

聯(lián)系郵箱：張煥國(guó)，liss@whu.edu.cn

通用量子計(jì)算機(jī)：理論、組成與實(shí)現(xiàn)

吳楠，宋方敏，LIXiang-Dong

摘要：通用量子計(jì)算機(jī)是指可以在不改變量子計(jì)算機(jī)物理組成和基本體系結(jié)構(gòu)的條件下針對(duì)所有可計(jì)算問(wèn)題進(jìn)行量子計(jì)算及其它量子信息處理的設(shè)備。通用量子計(jì)算機(jī)的研究和制造具有重要的理論和實(shí)際意義。要達(dá)成制造通用量子計(jì)算機(jī)的目標(biāo)，需要在底層量子物理設(shè)備、量子計(jì)算機(jī)體系結(jié)構(gòu)、量子資源調(diào)度和上層量子程序設(shè)計(jì)語(yǔ)言、量子算法及量子應(yīng)用軟件等多方面進(jìn)行努力。文中結(jié)合國(guó)內(nèi)外在上述各方面研究的最新進(jìn)展以及作者自身的研究結(jié)果，從計(jì)算機(jī)系統(tǒng)的角度為通用量子計(jì)算機(jī)的研究和制造繪制一幅藍(lán)圖，并詳細(xì)闡述了其中的困難與努力方向。

關(guān)鍵詞：量子計(jì)算；量子計(jì)算機(jī)；體系結(jié)構(gòu)；量子信息；量子程序設(shè)計(jì)語(yǔ)言；量子算法；物理實(shí)現(xiàn)

來(lái)源出版物：計(jì)算機(jī)學(xué)報(bào), 2016, 39(12): 2429-2445

聯(lián)系郵箱：吳楠，nwu@nju.edu.cn

量子計(jì)算與量子信息簡(jiǎn)介

王幫海，龔洪波

摘要：介紹量子計(jì)算與量子信息的產(chǎn)生背景、發(fā)展簡(jiǎn)史，量子比特與量子門(mén)的數(shù)學(xué)描述以及它們與物理概念之間的關(guān)系。介紹量子并行基礎(chǔ)的線性疊加、量子力學(xué)獨(dú)特資源的糾纏及其應(yīng)用。介紹量子密碼無(wú)條件安全的理論基礎(chǔ)、發(fā)展歷史，量子信息學(xué)研究、量子計(jì)算機(jī)實(shí)現(xiàn)的現(xiàn)狀，并對(duì)未來(lái)作展望。

關(guān)鍵詞：量子計(jì)算與量子信息；發(fā)展簡(jiǎn)史；基本概念；基本特性；基本原理

來(lái)源出版物：現(xiàn)代計(jì)算機(jī)（上下旬）, 2015 (15): 18-22

量子計(jì)算機(jī)的概念、原理與展望

張建奮

摘要：本文介紹了量子計(jì)算機(jī)的基本概念和基本原理，追尋量子計(jì)算機(jī)的歷史發(fā)展進(jìn)程，并展望未來(lái)發(fā)展前景。

關(guān)鍵詞：量子計(jì)算機(jī)；昆比特；態(tài)疊加原理；相干與退相干；量子并行；量子糾纏

來(lái)源出版物：物理通報(bào), 2015 (4): 125-128

量子計(jì)算機(jī)工程化現(xiàn)狀及挑戰(zhàn)

杜世平

摘要：量子計(jì)算和量子信息研究的是用量子力學(xué)系統(tǒng)能夠完成的信息處理任務(wù)，主要涉及量子力學(xué)、計(jì)算機(jī)科學(xué)和密碼學(xué)等不同領(lǐng)域的科學(xué)理論。更深層次地探討量子科學(xué)與工程技術(shù)，對(duì)于人們從本質(zhì)上認(rèn)識(shí)物理化學(xué)過(guò)程及生命科學(xué)等具有重要意義。介紹了量子科學(xué)技術(shù)相關(guān)研究成果，指出了當(dāng)前量子科學(xué)前沿課題、量子計(jì)算機(jī)工程化難題及對(duì)策。

關(guān)鍵詞：量子科學(xué)；量子計(jì)算；量子計(jì)算機(jī)工程化

來(lái)源出版物：軟件導(dǎo)刊, 2015, 14(3): 13-14

量子可逆邏輯電路雙向綜合算法

王冬，張曉蕾，朱長(zhǎng)江

摘要：量子可逆邏輯電路綜合技術(shù)是構(gòu)建量子計(jì)算機(jī)的關(guān)鍵技術(shù)之一。本文提出基于數(shù)組正反變換的量子可逆邏輯電路雙向綜合算法。該算法依據(jù)兩個(gè)數(shù)字間的漢明距離，利用鄰接矩陣的電路轉(zhuǎn)化規(guī)則，從正反兩個(gè)方向，生成任意給定置換的量子可逆邏輯電路。理論分析表明，該方法綜合 n量子電路最多需要（n-1）·2n+1個(gè)擴(kuò)展通用 Toffoli門(mén)。與其它同類算法相比，由于不需要窮盡搜索，該算法的時(shí)間復(fù)雜度和空間復(fù)雜度都有大幅度降低。此外，由于合理采用了擴(kuò)展通用Toffoli門(mén)，該算法可綜合任一置換（包括奇置換和偶置換）的量子可逆邏輯電路，且電路中量子門(mén)的數(shù)量大幅減少。

關(guān)鍵詞：量子可逆邏輯電路；量子計(jì)算；offoli門(mén)

來(lái)源出版物：小型微型計(jì)算機(jī)系統(tǒng), 2014, 35(5): 1111-1115

Error suppression for hamiltonian-based quantum computation using subsystem codes

來(lái)源出版物：Physical Review Letters, 2017, 118(3): 030504

Demonstration of a small programmable quantum computer with atomic qubits

Debnath, S; Linke, NM; Figgatt, C; et al.

Abstract: Quantum computers can solve certain problems more efficiently than any possible conventional computer. Small quantum algorithms have been demonstrated on multiple quantum computing platforms, many specifically tailored in hardware to implement a particular algorithm or execute a limited number of computational paths. Here we demonstrate a five-qubit trapped-ion quantum computer that can be programmed in software to implement arbitrary quantum algorithms by executing any sequence of universal quantum logic gates. We compile algorithms into a fully connected set of gate operations that are native to the hardware and have a mean fidelity of 98 per cent. Reconfiguring these gate sequences provides the flexibility to implement a variety of algorithms without altering the hardware. As examples, we implement the Deutsch–Jozsa and Bernstein–Vazirani algorithms with average success rates of 95 and 90 per cent, respectively. We also perform a coherent quantum Fourier transform on five trapped-ion qubits for phase estimation and period finding with average fidelities of 62 and 84 per cent, respectively. This small quantum computer can be scaled to larger numbers of qubits within a single register, and can be further expanded by connecting several such modules through ion shuttling or photonic quantum channels.

來(lái)源出版物：Nature, 2016, 536(7614): 63-66

聯(lián)系郵箱：Debnath; sdebnath@umd.edu

Digitized adiabatic quantum computing with a superconducting circuit

Barends, R; Shabani, A; Lamata, L; et al.

Abstract: Quantum mechanics can help to solve complex problems in physics and chemistry, provided they can be programmed in a physical device. In adiabatic quantum computing, a system is slowly evolved from the ground state of a simple initial Hamiltonian to a final Hamiltonian that encodes a computational problem. The appeal of this approach lies in the combination of simplicity and generality; in principle, any problem can be encoded. In practice, applications are restricted by limited connectivity, available interactions and noise. A complementary approach is digital quantum computing, which enables the construction of arbitrary interactions and is compatible with error correction, but uses quantum circuit algorithms that are problem-specific. Here we combine the advantages of both approaches by implementing digitized adiabatic quantum computing in a superconducting system. We tomographically probe the system during the digitized evolution and explore the scaling of errors with system size. We then let the full system find the solution to random instances of the one-dimensional Ising problem as well as problem Hamiltonians that involve more complex interactions. This digital quantum simulation of the adiabatic algorithm consists of up to nine qubits and up to 1,000 quantum logic gates. The demonstration of digitized adiabatic quantum computing in the solid state opens a path to synthesizing long-range correlations and solving complex computational problems. When combined with fault-tolerance, our approach becomes a general-purpose algorithm that is scalable.

來(lái)源出版物：Nature, 2016, 534(7606): 222-226

聯(lián)系郵箱：Barends, R; barends@google.com

Computational multiqubit tunnelling in programmable quantum annealers

Boixo, S; Smelyanskiy, VN; Shabani, A; et al.

Abstract: Quantum tunnelling is a phenomenon in which a quantum state traverses energy barriers higher than the energy of the state itself. Quantum tunnelling has been hypothesized as an advantageous physical resource for optimization in quantum annealing. However, computational multiqubit tunnelling has not yet been observed, and a theory of co-tunnelling under high-and low-frequency noises is lacking. Here we show that 8-qubit tunnelling plays a computational role in a currently available programmable quantum annealer. We devise a probe for tunnelling, a computational primitive where classical paths are trapped in a false minimum. In support of the design of quantum annealers we develop a nonperturbative theory of open quantum dynamics under realistic noise characteristics. This theory accurately predicts the rate of many-body dissipative quantum tunnelling subject to the polaron effect. Furthermore, we experimentally demonstrate that quantum tunnelling outperforms thermal hopping along classical paths for problems with up to 200 qubits containing the computational primitive.

來(lái)源出版物：Nature Communications, 2016, 7, 10327

聯(lián)系郵箱：Boixo, S; boixo@google.com

Real-time dynamics of lattice gauge theories with a few-qubit quantum computer

Martinez, EA; Muschik, CA; Schindler, P; et al.

Abstract: Gauge theories are fundamental to our understanding of interactions between the elementary constituents of matter as mediated by gauge bosons. However, computing the real-time dynamics in gauge theories is a notorious challenge for classical computational methods. This has recently stimulated theoretical effort, using Feynman’s idea of a quantum simulator, to devise schemes for simulating such theories on engineered quantum-mechanical devices, with the difficulty that gauge invariance and the associated local conservation laws (Gauss laws) need to be implemented. Here we report the experimental demonstration of a digital quantum simulation of a lattice gauge theory, by realizing (1+1)-dimensional quantum electrodynamics (the Schwinger model) on a few-qubit trapped-ion quantum computer. We are interested in the real-time evolution of the Schwinger mechanism, describing the instability of the bare vacuum due to quantum fluctuations, which manifests itself in the spontaneous creation of electron–positron pairs. To make efficient use of our quantum resources, we map the original problem to a spin model by eliminating the gauge fields in favour of exotic long-range interactions, which can be directly and efficiently implemented on anion trap architecture. We explore the Schwinger mechanism of particle–antiparticle generation by monitoring the mass production and the vacuum persistence amplitude. Moreover, we track the real-time evolution of entanglement in the system, which illustrates how particle creation and entanglement generation are directly related. Our work represents a first step towards quantum simulation of high-energy theories using atomic physics experiments—the long-term intention is to extend this approach to real-time quantum simulations of non-Abelian lattice gauge theories.

來(lái)源出版物：Nature, 2016, 534(7608): 516-519

聯(lián)系郵箱：Martinez, EA; esteban.martinez@uibk.ac.at

Ground state blind quantum computation on AKLT state

Morimae, T; Dunjko, V; Kashefi, E

Abstract: The blind quantum computing protocols (BQC) enable a classical client with limited quantum technology to delegate a computation to the quantum server (s) in such a way that the privacy of the computation is preserved. Here we present a new scheme for BQC that uses the concept of the measurement based quantum computing with the novel resource state of Affleck-Kennedy-Lieb-Tasaki (AKLT) chains leading to more robust computation. AKLT states are physically motivated resource as they are gapped ground states of a physically natural Hamiltonian in condensed matter physics. Our BQC protocol can enjoy the advantages of AKLT resource states, such as the cooling preparation of the resource state, the energy-gap protection of the quantum computation, and the simple and efficient preparation of the resource state in linear optics with biphotons.

關(guān)鍵詞：delegated quantum computing; measurement

based quantum computing; AKLT model

來(lái)源出版物：Quantum Information & Computation, 2015,

15 (3-4): 200-234

聯(lián)系郵箱：Morimae, T; morimae@gmail.com

Cryogenic control architecture for large-scale quantum computing

Hornibrook, JM; Colless, JI; Lamb, IDC; et al.

Abstract: Solid-state qubits have recently advanced to the level that enables them, in principle, to be scaled up into fault-tolerant quantum computers. As these physical qubits continue to advance, meeting the challenge of realizing a quantum machine will also require the development of new supporting devices and control architectures with complexity far beyond the systems used in today’s fewqubit experiments. Here, we report a microarchitecture for controlling and reading out qubits during the execution of a quantum algorithm such as an error-correcting code. We demonstrate the basic principles of this architecture using a cryogenic switch matrix implemented via high-electronmobility transistors and a new kind of semiconductor device based on gate-switchable capacitance. The switch matrix is used to route microwave waveforms to qubits under the control of a field-programmable gate array, also operating at cryogenic temperatures. Taken together, these results suggest a viable approach for controlling large-scale quantum systems using semi- conductor technology.

來(lái)源出版物：Physical Review Applied, 2015, 3(2): 024010聯(lián)系郵箱：Reilly, DJ; david.reilly@sydney.edu.au

Wigner function negativity and contextuality in quantum computation on rebits

Delfosse, N; Guerin, PA; Bian, J

Abstract: We describe a universal scheme of quantum computation by state injection on rebits (states with real density matrices). For this scheme, we establish contextuality and Wigner function negativity as computational resources, extending results of M. Howard et al. to two-level systems. For this purpose, we define a Wigner function suited to systems of n rebits and prove a corresponding discrete Hudson’s theorem. We introduce contextuality witnesses for rebit states and discuss the compatibility of our result with state-independent contextuality.

來(lái)源出版物：Physical Review X, 2015, 5(2): 021003

Contextuality supplies the ‘magic’ for quantum computation

Howard, M; Wallman, J; Veitch, V; et al.

Abstract: Quantum computers promise dramatic advantages over their classical counterparts, but the source of the power in quantum computing has remained elusive. Here we prove a remarkable equivalence betweenthe onset of contextuality and the possibility of universal quantum computation via ‘magic state’ distillation, which is the leading model for experimentally realizing a fault-tolerant quantum computer. This is a conceptually satisfying link, because contextuality, which precludes a simple ‘hidden variable’ model of quantum mechanics, provides one of the fundamental characterizations of uniquely quantum phenomena. Furthermore, this connection suggests a unifying paradigm for the resources of quantum information: the non-locality of quantum theory is a particular kind of contextuality, and non-locality is already known to be a critical resource for achieving advantages with quantum communication. In addition to clarifying these fundamental issues, this work advances the resource framework for quantum computation, which has a number of practical applications, such as characterizing the efficiency and trade-offs between distinct theoretical and experimental schemes for achieving robust quantum computation, and putting bounds on the overhead cost for the classical simulation of quantum algorithms.

來(lái)源出版物：Nature, 2014, 510(7505): 351-355

聯(lián)系郵箱：Emerson, J; jemerson@math.uwaterloo.ca

Quantum computations on a topologically encoded qubit

Nigg, D; Muller, M; Martinez, EA; et al.

Abstract: The construction of a quantum computer remains a fundamental scientific and technological challenge because of the influence of unavoidable noise. Quantum states and operations can be protected from errors through the use of protocols for quantum computing with faulty components. We present a quantum error-correcting code in which one qubit is encoded in entangled states distributed over seven trapped-ion qubits. The code can detect one bit flip error, one phase flip error, or a combined error of both, regardless on which of the qubits they occur. We applied sequences of gate operations on the encoded qubit to explore its computational capabilities. This seven-qubit code represents a fully functional instance of a topologically encoded qubit, or color code, and opens a route toward fault-tolerant quantum computing.

來(lái)源出版物：Science, 2014, 345(6194): 302-305

聯(lián)系郵箱：Nigg, D; daniel.nigg@uibk.ac.at

編輯：王微

Marvian, M; Lidar, DA

We present general conditions for quantum error suppression for Hamiltonian-based quantum computation using subsystem codes. This involves encoding the Hamiltonian performing the computation using an error detecting subsystem code and the addition of a penalty term that commutes with the encoded Hamiltonian. The scheme is general and includes the stabilizer formalism of both subspace and subsystem codes as special cases. We derive performance bounds and show that complete error suppression results in the large penalty limit. To illustrate the power of subsystem-based error suppression, we introduce fully two-local constructions for protection against local errors of the swap gate of adiabatic gate teleportation and the Ising chain in a transverse field.