Renormalization group analysis of superconductors at zero field: statics and dynamics

超导体中的临界涨落仍然知之甚少，特别是动力学涨落。这与超流氦和非阻挫磁系统的平衡和动力学临界性质形成对比。超导体中的困难在于热磁场涨落的处理，热磁场涨落与序参量涨落有很强的耦合。本项目的目的之一是修正以前的双圈重整化群计算的平衡涨落，并使用变分微扰理论恢复校正后的双圈结果。这将导致实验上可测量的超导体的临界特性。另一个目标是发展，第一次，在超导体中的动态临界现象，包括磁热波动的影响的理论。该项目的两个部分是互补的，适合博士生。

Critical fluctuations in superconductors are still poorly understood, in particular for dynamical fluctuations. This is in contrast to both equilibrium and dynamical critical properties of superfluid helium and non-frustrated magnetic systems. The difficulty in superconductors lies in the treatment of the thermal magnetic field fluctuations, which are strongly coupled to the fluctuations of the order parameter. One of the aims of the present project is to correct previous two-loop renormalization group calculations of equilibrium fluctuations, and to use Variational Perturbation Theory to resume the corrected two-loop result. This will lead to experimentally measurable critical properties of superconductors. The other aim is to develop, for the first time, a theory of dynamic critical phenomena in superconductors that includes the effect of magnetic thermal fluctuations. Both parts of the project are complementary and appropriate for a PhD student.