论文标题
当地的病房身份，用于自发损坏对称性的费米子系统中的集体激发
Local Ward identities for collective excitations in fermionic systems with spontaneously broken symmetries
论文作者
论文摘要
我们得出了表现出全球损坏的仪表对称性的费米管系统的病房身份。特别是，我们关注将量规场响应函数与顺序参数的横向敏感性联系起来的关系。我们发现前者的长波长和零能极限与后者低能扩张的系数有关。我们检查了三种物理病例：超导体，NéelAntiferromagnet和螺旋磁铁。在完全打破SU（2）自旋对称性的金属螺旋磁体的情况下，我们明确表明在随机相位近似中实现了病房的身份。随后，我们得出了旋转刚度和自旋波速度的微观表达式，可以将其插入低能模型中，以研究长波长骨体波动对平均场溶液顶部的影响。
We derive Ward identities for fermionic systems exhibiting a gauge symmetry that gets globally broken. In particular, we focus on the relation that connects the gauge field response functions to the transverse susceptibilities of the order parameter. We find that the long-wavelength and zero energy limit of the former are related to the coefficients of a low-energy expansion of the latter. We examine three physical cases: the superconductor, the Néel antiferromagnet and the spiral magnet. In the case of a metallic spiral magnet that completely breaks the SU(2) spin symmetry we explicitly show that the Ward identities are fulfilled within the random phase approximation. We subsequently derive microscopic expressions for the spin stiffnesses and spin wave velocities, which can be plugged into low energy models to study the effect of long-wavelength bosonic fluctuations on top of mean-field solutions.
