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利用量子不变量理论研究了任意随变化的强磁场中碱金属原子系统的演化问题,得到了此精确的演化态,并利用此精确的演化态求出了相应的Aharonov-Anandan相因子和绝热极限下的Berry相因子。将此系统精确的演化按哈密顿量的瞬音本征态展开,可以得到绝热近似似的任意阶修正。 相似文献
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本文考虑了经典演化方程和Schrodinger方程的类似性,指出具有缓变参数的经典演化方程的解会自然给出具有拓扑性质的几何相因子—我们称之为经典Berry相因子.我们给出了绝热条件破坏时非简并情况各级近似方程的通解.作为例子,详尽研究了带电粒子在绝热变化磁场中的运动,明显地得到了一个量子Berry相因子的经典模型.这个相因子在几何上可解释为参数空间中单位球面S2上厄米线丛的和乐. 相似文献
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利用量子不变量理论研究了任意随时间变化的强磁场中碱金属原子系统的演化问题,得到了此系统精确的演化态,并利用此精确的演化态求出了相应的Anaronov-Anandan相因子和绝热极限下的Berry相因子。将此系统精确的演化态按哈密顿量的瞬时本征态展开,可以得到绝热近似的任意阶修正。 相似文献
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本文在非相对论情况下,讨论了运动参照系中Schrodinger方程绝热近似解的性质和Berry相因子大坐标变换下的行为,对转动和平动参照系两种具体情况作了较为详尽的分析.这些讨论表明了Berry相因子的出现与参照系的选择有关.对于涉及到平动参照系的Bitter和Dubbers的中子极化问题.我们不仅在零级近似下给出理论和实验相符合的结果,而且还进一步分析了绝热条件破坏时可能出现的高阶效应. 相似文献
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关于Berry几何位相理论的推广 总被引:2,自引:0,他引:2
对于可参数化时间t的周期Hamiltonian系统,由non-adiabatic到adiabatic-limit的“严格”演变以获得Berry几何相γn(C)的问题.结果表明,存在“四种类型”的演变态,它们都可以满足在参数R空间中的同一条闭合曲线C上作这样的“严格演变”,并且还都可以获得同一个Berry几何相γn(C);而Berry发现这一几何相γn(C)时所考虑和采用的“演变态”,恰好属于本文“四种类型”的“严格”演变态之一的adiabaticapproximation情形.据此,可以把Berry几何位相理论推广到本文所研究的“四种类型”的“严格”演变中. 相似文献
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关于Berry几何位相理论的推广 总被引:1,自引:1,他引:0
对于可参数化时间t的周期Hamiltonian系统,由non–adiabatic到adiabatic–limit的“严格”演变以获得Berry几何相γn(C)的问题.结果表明,存在“四种类型”的演变态,它们都可以满足在参数R空间中的同一条闭合曲线C上作这样的“严格演变”,并且还都可以获得同一个Berry几何相γn(C);而Berry发现这一几何相γn(C)时所考虑和采用的“演变态”,恰好属于本文“四种类型”的“严格”演变态之一的adiabatic approximation情形.据此,可以把Berry几何位相理论推广到本文所研究的“四种类型”的“严格”演变中. 相似文献
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In general relativity, the equation of motion of the spin is given by the equation of parallel transport, which is a result of the space-time geometry. Any result of the space-time geometry cannot be directly applied to gauge theory of gravity. In gauge theory of gravity, based on the viewpoint of the coupling between the spin and gravitational field,an equation of motion of the spin is deduced. In the post Newtonian approximation, it is proved that this equation gives the same result as that of the equation of parallel transport. So, in the post Newtonian approximation, gauge theory of gravity gives out the same prediction on the precession of orbiting gyroscope as that of general relativity. 相似文献
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简述了近20多年以来我们在稀土发光和光谱理论方面所做的主要工作、取得的进展和成果。包括:(1)关于(4f)N组态内单光子跃迁强度:推广Judd-Ofelt三参量公式,在其中计入"J混合"(偶宇称晶场成分造成的)导致的修正;澄清了国际上关于Judd-Ofelt全参量公式中"静力学项"和"动力学项"相对正负号的争论(仍为负号)。(2)关于(4f)N组态内双光子过程强度:提出直接计算强度方法(放弃缔合近似,利用Ce3+的5d和左邻RE3+的(4f)N能级-波函资料,近似模拟出最重要的虚中间组态(4f)N-15d的能级-波函结构)来讨论和改进Judd-Ofelt缔合近似。(3)固体中声子辅助的稀土离子间能量传输理论:发现HLO理论关于单声子过程中的"干涉相消"实际只适合于对角过程,而非对角过程则是"干涉相加",因而,后者首要的是单声子而非双声子过程;同时,用"晶体格波模"取代"Debye模"描述能量传输中的声子,给出了新模型下计算对角和非对角过程速率等物理量的整套公式。并由之看出:波矢q=0和对应色散曲线扁平段的光学声子对单声子非对角过程速率有完全不能忽略的贡献,这些都不同于或超出于HLO理论。(4)提出和发展了分析指认4f-5d跃迁光谱的简单理论模型,用能量和跃迁强度同时进行近似拟合,成功地分析指认了从(4f)3到(4f)13离子在几种基质中的4f→5d吸收(激发)谱,也成功用于若干5d→4f辐射谱。(5)对跃迁的初末晶场态同时引用有效自旋哈密顿描述稀土离子间超交换作用,成功地解释了低温10 K时立方结构的纯稀土冰晶石晶体Cs2NaLnCl6(Ln=Er,Yb)等的吸收谱中0声子线(量级为几个cm-1)的精细分裂。 相似文献
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The luminescence spectra of AgCl microcrystals were measured in two different regimes: in the regime of excitation of stationary luminescence and in the regime of photostimulated burst of luminescence. Differences between the spectra of stationary luminescence and the spectra of photostimulated-luminescence burst in the range between 430 and 590 nm have been found. The luminescence spectra are complex; the ratio of intensities for elementary components changes with the technique of excitation. Differences in the form and composition of complex luminescence bands obtained under different conditions of registration are attributed to the recombination interaction of the luminescence centers. It is shown that analysis of the dependences of intensity ratios for the elementary components of a complex luminescence band on the exciting-radiation intensity allows one to evaluate the mechanism of recombination in elementary bands provided that the mechanism is known for at least one luminescence band.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 1, pp. 85–89. January–February, 2005. 相似文献
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M.G. Edmunds 《Contemporary Physics》2013,54(4):263-285
Astronomers have two approaches to trying to determine the age of the Universe. They can estimate the ages of individual objects in the Universe and specifically in our Galaxy. These estimates use either the observed properties of stars and theoretical ideas concerning stellar evolution or the abundances of long-lived radioactive isotopes and their decay products. Alternatively they can use cosmological theories and observations to try to determine the age of the entire Universe. Obviously the Universe must be older than its component parts but neither of the above methods is sufficiently reliable that this is true of the deduced ages. As a result, it is from time to time reported that some object in the Universe is older than the Universe itself. In this article we discuss the methods that are currently being used to determine the age and we emphasize the problems in obtaining reliable results. It is not at present possible to provide a definite value for the age of the Universe. 相似文献
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H. Dandache 《Il Nuovo Cimento D》1989,11(10):1501-1506
Summary The semi-empirical Hugoniot equation of state is obtained by using the third-order tangency between the isentropic and the
Hugoniot curves at the origin of coordinates. The results of this model are in good agreement with Carter’s experimental data
for fourteen elements from the lanthanides series in the lower phase only.
Due to postal troubles with Lebanon, it was impossible to send proffs to the author as he requested. 相似文献
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In general relativity, the equation of motion of the spin is given by the equation of parallel transport, which is a result of the space-time geometry. Any result of the space-time geometry cannog be directly applied to gauge theory of gravity. In gauge theory of gravity, based on the viewpoint of the coupling between the spin and gravitational field, an equation of motlon of the spin is deduced. In the post Newtonian approximation, it is proved that this equation gives the same result as that of the equation of parallel transport. So, in the post Newtonian approximation, gauge theory of gravity gives out the same prediction on the precession of orbiting gyroscope as that of general relativity. 相似文献