共查询到19条相似文献,搜索用时 76 毫秒
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文章首先概述了近年国际文献中关于量子绝热近似和绝热条件的不自洽性的研究.叙述了文献中关于绝热近似不自洽性的论证和争论.然后引入文章作者的观点,从不同于国外文献的角度出发指出应当正确地理解瞬时本征函数的相位问题,从这个相位的正确处理,得出结论:(1)MS不自洽的存在,不因计及几何相位而消除;(2)量子几何相位不自洽是不存在;(3)现时的标准的绝热近似条件不是充分条件. 相似文献
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本文利用高阶量子绝热近似方法讨论了量子微腔驻波场中三能级暗态原子与光场相互作用中原子质心运动对电子,光场系统动力学的影响。文章分析了绝热近似成立的条件以及非绝热因子对动力学演化的影响。文中还计算了原子在腔中的非绝热跃迁几率及各部分能量分布的平均值。 相似文献
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教学研究:介绍量子力学几个基本概念——兼答《关于量子几何相位的评注》中的几个主要问题 总被引:4,自引:4,他引:0
介绍了量子绝热定理的物理含义及成立的条件,认为有关主要献(Aharonov-Anandan,Bohm,孙昌璞等)的表述是正确的,而《关于量子几何相位的评注》^[1](以下简称《评注》)相应的表述不完全正确。在此基础上,认为这些献和教材(R.Shankar)得出的涉及Berry绝热相位的一些论述(不含Berry绝热相因子的瞬时能量本征态不满足含时Schroedinger方程等)也是正确的,而《评注》的论述与此相反。《评注》认为只有γn(C)才是Berry相位。本作则倾向于把γn(t)叫做Berry绝热相位,而把γn(C)=γn(T)-γn(0)叫做几何相位(geometric phase)^[2]。 相似文献
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利用绝热演化,文章提出一种新的方法以实现量子相位门,这种相位移动既非源于动力学过程,也非源于几何操纵,它来源于暗态本身的演化,基于绝热演化的优点,这种量子逻辑门对实验参量的起伏不敏感,与几何相位门相比,这种相位门更简单,并且保真度可得到进一步提高。文章对这种相位门做一简述。 相似文献
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在绝热演化中的几何相位(即Berry相位)被推广到包括非本征态的一般量子态.这个新的几何相位同时适用于线性量子系统和非线性量子系统.它对于后者尤其重要因为非线性量子系统的绝热演化不能通过本征态的线性叠加来描述.在线性量子系统中,新定义的几何相位是各个本征态Berry相位的权重平均. 相似文献
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文章研究了自旋为1的粒子在旋转磁场中的几何相位和动力学相位.推导出如何计算自旋为1的粒子在绝热和非绝热演化中的几何相位和动力学相位公式,并利用这些公式计算其相位.最后我们讨论了三种情况下的Berry相位,当考虑ω1<<ω时,系统处于绝热近似,此时,几何相位就是Berry相位. 相似文献
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由于绝热条件几何相位量子逻辑门存在非绝热差错与退相干差错这一冲突,因此在拓扑量子计算中需要设计非绝热条件几何相门,以克服这一不足.证明螺旋光纤系统内光子有效哈密顿量恰好是一个Wang Matsumoto型哈密顿量,因此螺旋光纤系统能自动产生非绝热条件几何相移.同时还证明在螺旋光纤方案中,由极化光子与螺旋光纤相互作用哈密顿量所导致的动力学相位为零(这正是拓扑量子计算所要求的),以及在螺旋光纤系统中可以通过控制极化光子初始波矢,从而较容易获得条件初始态.总之,螺旋光纤系统方案能自动满足Wang与Matsumoto的核磁共振方案中为实现非绝热条件几何相移所提出的全部条件与要求.
关键词:
几何相位
螺旋光纤系统
Wang Matsumoto型哈密顿量
拓扑量子计算 相似文献
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本文引介绝热量子计算理论评述量子绝热定理最新的应用。基于量子绝热方法在最新的前沿领域量子计算中建立量子绝热算法。我们引介"局域量子绝热",并考虑了这一局域绝热概念对量子算法的可能应用。 相似文献
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绝热量子计算理论引介 总被引:2,自引:0,他引:2
本文引介绝热量子计算理论评述量子绝热定理最新的应用.基于量子绝热方法在最新的前沿领域量子计算中建立量子绝热算法.我们引介"局域量子绝热",并考虑了这一局域绝热概念对量子算法的可能应用. 相似文献
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In this paper, we study a kind of nonlinear model of adiabatic evolution in quantum search problem. As will be seen here, for this problem, there always exists a possibility that this nonlinear model can successfully solve the problem, while the linear model can not. Also in the same setting, when the overlap between the initial state and the final stare is sufficiently large, a simple linear adiabatic evolution can achieve O(1) time efficiency, but infinite time complexity for the nonlinear model of adiabatic evolution is needed. This tells us, it is not always a wise choice to use nonlinear interpolations in adiabatic algorithms. Sometimes, simple linear adiabatic evolutions may be sufficient for using. 相似文献
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We discuss the logic implementation of quantum gates in the framework of the quantum adiabatic method, which uses the language of ground states, spectral gaps and Hamiltonians instead of the standard unitary transformation language. 相似文献
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In this paper, we discuss the question of the minimum time needed for any state of a given quantum system to evolve into a distinct (orthogonal) state. This problem is relevant to deriving physical limits in quantum computation and quantum information processing. Here, we consider both cases of nonadiabatic and adiabatic evolution and we derive the Hamiltonians corresponding to the minimum time evolution predicted by the Margolus–Levitin theorem. 相似文献
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Unstructured Adiabatic Quantum Search 总被引:2,自引:0,他引:2
In the adiabatic quantum computation model, a computational procedure is described by the continuous time evolution of a time dependent Hamiltonian. We apply this method to the Grover's problem, i.e., searching a marked item in an unstructured database. Classically, the problem can be solved only in a running time of order O(N) (where N is the number of items in the database), whereas in the quantum model a speed up of order
has been obtained. We show that in the adiabatic quantum model, by a suitable choice of the time-dependent Hamiltonian, it is possible to do the calculation in constant time, independent of the the number of items in the database. However, in this case the initial time-complexity of
is replaced by the complexity of implementing the driving Hamiltonian. 相似文献
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强磁场中氢分子离子H2^+能级的绝热及绝热变分计算 总被引:2,自引:2,他引:0
采用绝热近拟和绝热变分近似两种方法,计算了均匀强磁场(10≤β≤1000)中H2^+的σg,πu,δg,Φu,γg,ηu态的能有有原子核间的平衡距离,并与前人的结果进行了比较。 相似文献
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L. A. Gribov 《Journal of Applied Spectroscopy》2006,73(3):323-327
The concept of the adiabatic approximation is introduced from a few new standpoints, and the conditions are refined under
which we can assume that the total energy of an electronic-vibrational (vibronic) state is the sum of the energies of the
“electronic” and the “nuclear” problems and the wave function is represented as the product of the corresponding functions.
An expression exactly corresponding to such an approximation is considered for the optical transition matrix element, and
its individual terms are analyzed for any change in the geometric structure of the molecule upon optical excitation.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 3, pp. 290–293, May–June, 2006. 相似文献
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This paper presents and implements a specified partial adiabatic search algorithm on a quantum circuit. It studies the minimum energy gap between the first excited state and the ground state of the system Hamiltonian and it finds that,in the case of M = 1,the algorithm has the same performance as the local adiabatic algorithm. However,the algorithm evolves globally only within a small interval,which implies that it keeps the advantages of global adiabatic algorithms without losing the speedup of the local adiabatic search algorithm. 相似文献