量子信息技术在金融业的探索应用

上世纪七十年代,量子信息技术在量子力学和信息科学的交叉研究中而产生,其主要研究方向包括量子通信、量子计算、量子存储与量子传感等。近年来,随着量子信息技术的研究取得重大突破,量子信息技术的应用价值进一步凸显。本文首先介绍量子信息技术的起源及定义;其次简要介绍量子通信、量子计算、量子存储和量子传感等技术,并结合金融行业发展特点,探索出各项量子信息技术在金融业的应用场景;最后详细分析量子信息技术给金融业带来的巨大挑战,并给出具体发展建议。     

量子计算及量子算法研究进展

量子相干性和量子纠缠等特性为量子计算带来了完全不同于经典计算的独特运算方式,量子计算表现出的并行性更是令经典运算望尘莫及。Shor算法的提出完全展示了量子算法在解决某些经典问题时的优势,接踵而至的Grover搜索算法进一步诠释了量子计算的威力。此后,算法“量子化”在国际上掀起了研究的热潮,尤其在量子智能算法方面取得了不错的成果。文章首先介绍量子计算的发展现状和基本原理;然后列举三种典型的量子算法,展示量子计算的优越性;最后介绍该领域的研究进展。     

量子搜索及量子智能优化研究进展

为了提高智能优化算法的收敛速度及优化性能,目前国内外将量子计算机制和传统智能优化相融合,研究和提出了多种量子进化算法及量子群智能优化算法;为了进一步推动该领域的研究进展,系统地介绍了国内外提出的多种量子搜索及量子智能优化算法,其中包括量子搜索、量子衍生进化、量子神经网络三个方面内容;总结出目前改进量子搜索算法的主要机制和量子计算与传统智能计算的主要融合方式,并展望了量子搜索和量子智能优化有待进一步研究和需要解决的问题。     

一种面向含噪中尺度量子技术的量子-经典异构计算系统

量子计算有望加速解决经典计算难以解决的问题,如质因子分解、量子化学模拟等.已有单个量子系统可集成大于50个含噪声的固态量子比特,并在特定的计算任务上超越了经典计算机,标志含噪中尺度量子(noisy intermediate-scale quantum,NISQ)计算时代的到来.随着人们可在单个系统中集成越来越多的量子比特,如何将量子比特与控制硬件、软件开发环境、经典计算资源集成得到完整可用的量子计算系统,是一个有待进一步明确的问题.对比了量子计算与经典计算在控制及执行上的异同,并在此基础上提出了面向NISQ时代的量子-经典异构系统.以一个典型的NISQ算法(迭代相位估计算法)为例,介绍了量子算法从软件描述到硬件执行的整体流程,及与该过程相关的高级程序设计语言、编译器、量子软硬件接口和硬件等.在此基础上,讨论了流程中各个层次在NISQ时代面临的挑战.旨在从工程实现的视角,从宏观层面为读者(尤其是量子计算初学者)介绍量子计算系统,希望可以促进人们对NISQ时代下量子计算系统整体结构的理解,并激发更多相关研究.     

量子计算

近几年来,量子计算机逐渐引起人们的关注。对于计算机科技人员,量子计算机似乎高深莫测。文章是专门为那些不懂量子力学而又想了解量子计算机的计算机工作者撰写的。介绍了和量子计算有关的术语和符号,并着重阐明一个n位量子寄存器为何能存储2^n个n位数？量子计算机的一次操作为何能计算所有x的f(x)？对于解栽些问题,量子计算机为何能有惊人的运算速度？除了上面3个问题外,还将介绍基本的量子逻辑门和量子逻辑网络,接着介绍一个量子算法,然后介绍量子计算机的组织结构,最后是讨论,将评价量子计算机的优势和弱点,并讨论量子计算机的物理实现和对量子计算的展望。     

电脑文摘

９９０１３量子计算机进入实验阶段／／计算机工程．－１９９９（１）．－３～４首先简要介绍分层计算的制约;其次介绍最近量子信息的开发,在理论和实践两方面的通信和计算,诸如量子逻辑门、量于密码学、量子交缠性、超距传输的实验性实现、量子算法的首次实验性实现,量子因子分解、量子纠错码以及基于硅片的原子自旋量子计算机;最后讨论克服非相干性困难的方法。９９０１４在客户／服务器结构中利用ＯＤＢＣ访问数据库的两种方法／计算机工程．－１９９９（１）．－５４～５６ＯＤＢＣ是一种数据库与应用程序之间的调用级别接口。与嵌…     

量子算法与量子衍生算法

随着经典计算发展日趋缓慢,量子计算正逐渐成为研究领域的关注热点.该文简要介绍了量子计算的基本原理.接着,从当前量子计算领域中的两个活跃研究方向——量子算法和量子衍生技术研究出发对整个量子算法领域主要发展脉络进行梳理并总结目前量子计算研究的发展规律.最后,该文针对这两个方向提出了若干量子计算领域的发展趋势.通过对量子计算研究领域的综述和展望,对后续量子计算研究发展具有一定的指导意义.     

辅助量子比特驱动型通用盲量子计算

应用量子隐形传态将Broadbent等人提出的通用盲量子计算(universal blind quantum computation)模型和辅助量子比特驱动型量子计算(ancilla-driven universal quantum computation)模型进行结合, 构造一个新的混合模型来进行计算。此外, 用计算寄存器对量子纠缠的操作来代替量子比特测量操作。因为后者仅限于两个量子比特, 所以代替后的计算优势十分明显。基于上述改进, 设计了实现辅助驱动型通用盲量子计算的协议。协议的实现, 能够使Anders等人的辅助驱动型量子计算增强计算能力, 并保证量子计算的正确性, 从而使得参与计算的任何一方都不能获得另一方的保密信息。     

SHOR量子算法的原理与程序模拟

本文首先介绍大数质因子分解的Shor量子算法的原理、实现步骤和实现方法，然后用现存的模拟器在常规计算机上加以模拟。最后讨论了Shor算法模拟的意义，并对量子计算提出了看法。     

基于IBM量子计算云服务的量子傅里叶变换实现

Shor算法能够相对经典大整数分解算法实现指数加速,从而直接威胁到了RSA密码体制,而量子傅里叶变换是Shor算法中的一个关键变换,也能够相对经典离散傅里叶变换实现指数加速,从而引起了广泛关注。主要针对量子傅里叶变换的实现方案进行研究。首先介绍了IBM公司量子计算云服务的编程基础,随后设计了3比特量子傅里叶变换的量子线路,最后在IBM公司5超导量子比特的量子计算芯片上进行了实验验证。     

Service differentiation and fair sharing in distributed quantum computing

In the future, quantum computers will become widespread and a network of quantum repeaters will provide them with end-to-end entanglement of remote quantum bits. As a result, a pervasive quantum computation infrastructure will emerge, which will unlock several novel applications, including distributed quantum computing, that is the pooling of resources on multiple computation nodes to address problem instances that are unattainable by any individual quantum computer. In this paper, we first investigate the issue of service differentiation in this new environment. Then, we define the problem of how to select which computation nodes should participate in each pool, so as to achieve a fair share of the quantum network resources available. The analysis is performed via an open source simulator and the results are fully and readily available.     

A Survey on quantum computing technology

The power of quantum computing technologies is based on the fundamentals of quantum mechanics, such as quantum superposition, quantum entanglement, or the no-cloning theorem. Since these phenomena have no classical analogue, similar results cannot be achieved within the framework of traditional computing. The experimental insights of quantum computing technologies have already been demonstrated, and several studies are in progress. Here we review the most recent results of quantum computation technology and address the open problems of the field.     

Mathematical models of quantum computation

In this paper, we introduce two mathematical models of realistic quantum computation. First, we develop a theory of bulk quantum computation such as NMR (Nuclear Magnetic Resonance) quantum computation. For this purpose, we define bulk quantum Turing machine (BQTM for short) as a model of bulk quantum computation. Then, we define complexity classes EBQP, BBQP and ZBQP as counterparts of the quantum complexity classes EQP, BQP and ZQP, respectively, and show that EBQP=EQP, BBQP=BQP and ZBQP=ZQP. This implies that BQTMs are polynomially related to ordinary QTMs as long as they are used to solve decision problems. We also show that these two types of QTMs are also polynomially related when they solve a function problem which has a unique solution. Furthermore, we show that BQTMs can solve certain instances of NP-complete problems efficiently. On the other hand, in the theory of quantum computation, only feed-forward quantum circuits are investigated, because a quantum circuit represents a sequence of applications of time evolution operators. But, if a quantum computer is a physical device where the gates are interactions controlled by a current computer such as laser pulses on trapped ions, NMR and most implementation proposals, it is natural to describe quantum circuits as ones that have feedback loops if we want to visualize the total amount of the necessary hardware. For this purpose, we introduce a quantum recurrent circuit model, which is a quantum circuit with feedback loops. LetC be a quantum recurrent circuit which solves the satisfiability problem for a blackbox Boolean function includingn variables with probability at least 1/2. And lets be the size ofC (i.e. the number of the gates inC) andt be the number of iterations that is needed forC to solve the satisfiability problem. Then, we show that, for those quantum recurrent circuits, the minimum value ofmax(s, t) isO(n ²2 ^n/3). Tetsuro Nishino, D.Sc.: He is presently an Associate Professor in the Department of Information and Communication Engineering, The University of Electro-Communications. He received the B.S., M.S. and D.Sc degrees in mathematics from Waseda University, in 1982, 1984 and 1991 respectively. From 1984 to 1987, he joined Tokyo Research Laboratory, IBM Japan. From 1987 to 1992, he was a Research Associate of Tokyo Denki University, and from 1992 to 1994, he was an Associate Professor of Japan Advanced Institute of Science and Technology, Hokuriku. His main interests are circuit complexity theory, computational learning theory and quantum complexity theory.     

Quantum Computation: a Tutorial

This tutorial is the first part of a series of two articles on quantum computation. In this first paper, we present the field of quantum computation from a broad perspective. We review the mathematical background and informally discuss physical implementations of quantum computers. Finally, we present the main primitives used in quantum algorithms.     

Classically-controlled Quantum Computation

It is reasonable to assume that quantum computations take place under the control of the classical world. For modelling this standard situation, we introduce a Classically-controlled Quantum Turing Machine (CQTM) which is a Turing machine with a quantum tape for acting on quantum data, and a classical transition function for a formalized classical control. In CQTM, unitary transformations and quantum measurements are allowed. We show that any classical Turing machine is simulated by a CQTM without loss of efficiency. Furthermore, we show that any k-tape CQTM is simulated by a 2-tape CQTM with a quadratic loss of efficiency. The gap between classical and quantum computations which was already pointed out in the framework of measurement-based quantum computation (see [S. Perdrix, Ph. Jorrand, Measurement-Based Quantum Turing Machines and their Universality, arXiv, quant-ph/0404146, 2004]) is confirmed in the general case of classically-controlled quantum computation. In order to appreciate the similarity between programming classical Turing machines and programming CQTM, some examples of CQTM will be given in the full version of the paper. Proofs of lemmas and theorems are omitted in this extended abstract.     

量子计算机的研究与应用

介绍了量子计算的最新研究方向,简述了量子计算和量子信息技术在保密通信、量子算法、数据库搜索等重要领域的应用。分析了量子计算机与经典计算机相比所具有的优点和目前制约量子计算机应用发展的主要因素,最后展望了其未来发展趋势。     

Exponential Separation of Quantum and Classical Online Space Complexity

Although quantum algorithms realizing an exponential time speed-up over the best known classical algorithms exist, no quantum algorithm is known performing computation using less space resources than classical algorithms. In this paper, we study, for the first time explicitly, space-bounded quantum algorithms for computational problems where the input is given not as a whole, but bit by bit. We show that there exist such problems that a quantum computer can solve using exponentially less work space than a classical computer. More precisely, we introduce a very natural and simple model of a space-bounded quantum online machine and prove an exponential separation of classical and quantum online space complexity, in the bounded-error setting and for a total language. The language we consider is inspired by a communication problem (the disjointness function) that Buhrman, Cleve and Wigderson used to show an almost quadratic separation of quantum and classical bounded-error communication complexity. We prove that, in the framework of online space complexity, the separation becomes exponential.     

Quantum Computation: From a Programmer’s Perspective

This paper is the second part of a series of two articles on quantum computation. If the first part was mostly concerned with the mathematical formalism, here we turn to the programmer’s perspective. We analyze the various existing models of quantum computation and the problem of the stability of quantum information. We discuss the needs and challenges for the design of a scalable quantum programming language. We then present two interesting approaches and examine their strengths and weaknesses. Finally, we take a step back, and review the state of the research on the semantics of quantum computation, and how this can help in achieving some of the goals.     

经典逻辑门与量子逻辑门之比较

本文通过经典逻辑门与量子逻辑门之比较,论述了量子计算的特点、量子算法的巨大威力及量子逻辑门的实现问题。