A variational approach to disordered systems
A variational approach to disordered systems
复制标题
无序系统的变分方法
DOI：
10.1088/0022-3719/8/22/015
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发表时间：
1975
期刊：
影响因子：
--
通讯作者：
P. R. Best
中科院分区：
文献类型：
--
作者：
P. Lloyd;P. R. Best
导出了一个包含本征态密度函数的精确变分原理。这种变分原理不同于先前发表的猜想，并已应用于两种不同类型的带尾问题，以证明其有效性。然后，一个密切相关的关于随机介质的复杂自能的变分分析被表述出来，并在适当的情况下显示，导致CPA近似以及这种近似的聚类推广。结果表明，这种聚类泛化可以准确地再现一些计算机生成的态密度。
An exact variational principle involving the density-of-eigenstates function is derived. This variational principle differs from previously published conjectures, and has been applied to two different types of band-tailing problems in order to demonstrate its usefulness. A closely related variational ansatz concerning the complex self-energy of a random medium is then formulated, and is shown, under the appropriate circumstances, to lead to the CPA approximation as well as to cluster generalizations of this approximation. It is shown that such cluster generalizations can accurately reproduce some computer-generated density of states.