共查询到18条相似文献,搜索用时 125 毫秒
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从本征函数理论出发,本文介绍了求解第一类格林函数的本征函数法。从而对格林函数的本征函数法建立进行一般的理论概括。最后举例说明应用。 相似文献
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运用随机量子化方法,讨论了具有凝聚相的玻色子系统的格林函数.得到了带有反常格林函数的 Dyson 方程,并用矩阵形式下的 Langevin 方程得到了同一结果. 相似文献
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着重研究了Neumann静电边值问题中对称性格林函数的制作,并以同心球壳之间空间格林函数的制作为例加以说明,同时给出了Dirichlet静电边值问题的相应结果。 相似文献
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低维材料不断涌现的新奇性质吸引着科学研究者的目光. 除了电子的量子输运行为之外, 人们也陆续发现和确认了热输运中显著的量子行为, 如 热导低温量子化、声子子带、尺寸效应、瓶颈效应等. 这些小尺度体系的热输运性质可以很好地用非平衡格林函数来描述. 本文首先介绍了量子热输运的特性、声子非平衡格林函数方法及其在低维纳米材料中的研究进展; 其次回顾了近年来在 一系列低维材料中发现的热-自旋输运现象. 这些自旋热学现象展现了全新的热电转换机制, 有助于设计新型的热电转换器件, 同时也给出了用热产生自旋流的新途径; 最后介绍了线性响应理论以及在此理论框架下结合声子、电子非平衡格林函数方法进行的一些有益的探索. 量子热输运的研究对热效应基础研究以及声子学器件、能量转换器件的发展有着不可替代的重要作用. 相似文献
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利用递推格林函数技术计算了多终端量子体系的电子输运特性,首先运用递归方法给出介观 或量子体系的格林函数. 然后利用散射矩阵和输运方程给出体系的电导方程,可以将多终端 的输运简化为双终端的输运方程,以便得到体系电子输运的谱结构. 计算结果表明,由于中 间节点的存在,使器件的传输谱偏离一维链的对称性,在低能量端出现一个新的电导峰值. 此外,本方法可以被应用到各种复杂的带有吸附结构量子体系输运的研究中.
关键词:
格林函数
散射矩阵
量子体系 相似文献
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Alexander I. Pegarkov 《International Journal of Theoretical Physics》2002,41(8):1597-1625
A Green function of time-independent multichannel Schrödinger equation is considered in matrix representation beyond a perturbation theory. Nonperturbative Green functions are obtained through the regular in zero and at infinity solutions of the multichannel Schrödinger equation for different cases of symmetry of the full Hamiltonian. The spectral expansions for the nonperturbative Green functions are obtained in simple form through multichannel wave functions. The developed approach is applied to obtain simple analytic equations for the Green functions and transition matrix elements for compound multipotential system within quasiclassical approximation. The limits of strong and weak interchannel interactions are studied.Alexander I. Pegarkov:On leave from Physics Faculty 相似文献
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《Physics letters. A》2020,384(23):126573
We construct an expression for the Green function of a differential operator satisfying nonlocal, homogeneous boundary conditions starting from the fundamental solution of the differential operator. This also provides the solution to the boundary value problem of an inhomogeneous partial differential equation with inhomogeneous, nonlocal boundary conditions. The construction applies for a broad class of linear partial differential equations and linear boundary conditions. 相似文献
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It has been generally recognized that Green function integrated with Boundary Element Method (BEM) has advantages in dimensional
reduction, high accuracy and satisfaction of the radiation condition at infinity, etc. Recently, the computational technique
has rapidly developed and the orient-object programming has been widely applied, whereas the attribute of abstraction and
the integration of Green function employed in BEM have not been discovered yet. In this work the abstraction and integration
of Green function are carried out for soil dynamics problems, and the procedure of the object-oriented calculation method
is presented. Based on the Green function developed for the two-phase saturated medium, the response of the wave field to
tunnel subjected to dynamic loading is calculated, and the transient solution as well as the time history of response is obtained.
Supported by the National Natural Science Foundation of China (Grant No. 10572129) 相似文献
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NguyenSuanHan 《理论物理通讯》2002,37(2):167-172
This paper is devoted to the one-loop calculation of the fermion Green function in QED within the framework of the minimal quantization method,based on an explicit solution of the constraint equations and the gangeinvariance principle.The relativistic invariant expression for the fermion Green function with correct analytical properties is obtained. 相似文献
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We extend the Green function approach to quantum transport through an anisotropic molecular magnet system with the help of Hubbard operators. Based on the single molecular magnet model, we reformulate the large spin and the total Hamiltonian in the language of Hubbard operators and obtain analytical expressions of the retarded Green function in sequential tunneling and Kondo regimes. In addition to this, we show the connection of our method to the master equation method in sequential regime and discuss a simple isotropic case in Kondo regime, in which we find a three-peak Kondo structure, a feature characterizing the isotropic exchange interaction between the localized electron and large spin. 相似文献