The Goldstone theorem and the Jahn-Teller effect
The Goldstone theorem and the Jahn-Teller effect
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戈德斯通定理和 Jahn-Teller 效应
DOI：
10.1088/0370-1328/91/1/331
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发表时间：
1967
期刊：
影响因子：
--
通讯作者：
A. Stoneham
中科院分区：
文献类型：
--
作者：
J. Sarfatt;A. Stoneham
Goldstone定理要求对称性破缺的多体系统有一个激发支路，它的频率在无限大的波长范围内趋于零。我们处理这样一个系统，其中对称性的破缺来自于引起Jahn-Teller效应的项。当没有Jahn-Teller项时，我们详细讨论的两个激发分支在无限波长都有有限的频率；这一项的引入迫使一个分支在无限波长有零频率，这与Goldstone定理是一致的。本文的主要观点是对Goldstone猜想的这一显著例证。讨论了激发分支的一些更简单的特征，它们似乎在文献中没有被详细讨论。处于两重简并E基态的离子系统可能会表现出这样的激发，其特征速度将比声音的特征速度小得多。
The Goldstone theorem requires that a many-body system with broken symmetry has an excitation branch, whose frequency tends to zero in the limit of infinite wavelength. We treat a system where the broken symmetry comes from the terms which give rise to the Jahn-Teller effect. Both the excitation branches we discuss in detail have finite frequencies at infinite wavelength when there is no Jahn-Teller term; the introduction of this term forces one branch to have zero frequency at infinite wavelength, in agreement with the Goldstone theorem The main point of this paper is this striking illustration of Goldstone's conjecture. Some of the simpler features of the excitation branches are discussed, they do not appear to have been treated in detail in the literature. Systems of ions in twofold degenerate E ground states may exhibit such excitations, which will have a characteristic velocity considerably less than that of sound.