结构相变的规范场理论

 本文首先从场论的观点出发，构造了完整晶体的拉氏函数——晶体声子场的拉氏函数。利用晶体声子场在局域群G=SO(3)下的对称性破缺，引入了缺陷规范场。借助于场论中的真空对称性自发破缺和缺陷规范场理论，很自然地把缺陷引到结构相变的研究中。我们给出了相变温度θ_c，入点的热容量的跃变值ΔC_v，及序参数Φ_i的计算公式。从公式中，明显可看出缺陷对相变温度、热容变化值及序参数的影响。另外，我们确定了缺陷规范场理论中的耦合常数g。最后，我们给出了由压力引起的结构相变（如冲击相变）的一种可能的机理。

GAUGE FIELD THEORY OF STRUCTURAL TRANSITIONS

From the viewpoint of gauge field theory, we have constructed the Lag-rangian function of perfect crystal--the Lagrangian function of phonon field. Becauseof the break of symmetry of phonon field under the local group G=SO(3) we could introduce the gauge field of defects. With the aid of the spontaneous symmetry break of vacuum state and gauge field theory of defects, this paper presents the formulae of transition temperature c, jump quantity of C at transition AC, and order parameter respectively. From these formulae, we can easily show the effect of defect on structural transition. Therefore, defect has been naturally introduced into the study of structural transition, and the mechanism of structural transition has also been discussed. Finally, we determined the coupled constant g of gauge field theory of defects.