论文标题
超流相变的重新归一化组研究:可压缩性的影响
Renormalization group study of superfluid phase transition: effect of compressibility
论文作者
论文摘要
在外部搅拌和延伸过程的存在下,考虑了超流体系统中的动态临界行为。后者是通过高斯随机速度合奏产生的,具有白色噪声特征在时间变量和自相似的空间依赖性中。这项工作的主要重点是分析可压缩模式对临界行为的影响。该模型是通过随机Langevin方程式制定的,然后将其重新铸造为Janssen-Demanicis反应形式主义。采用现场理论扰动重新归一化组方法,我们分析了模型的大规模特性。在双$(\ Varepsilon,y)$扩展方案中,对领先的一环近似进行了明确的计算,其中$ \ varepsilon $是偏离临界尺寸$ d_c = 4 $和$ y $的偏差。总体上,总共可以观察到五个不同的普遍性类别。与不可压缩的情况相反,我们发现可压缩性会导致非平凡渐近方案的增强和稳定。
Dynamic critical behavior in superfluid systems is considered in a presence of external stirring and advecting processes. The latter are generated by means of the Gaussian random velocity ensemble with white-noise character in time variable and self-similar spatial dependence. The main focus of this work is to analyze an effect of compressible modes on the critical behavior. The model is formulated through stochastic Langevin equations, which are then recast into Janssen-De Dominicis response formalism. Employing the field-theoretic perturbative renormalization group method we analyze large-scale properties of the model. Explicit calculations are performed to the leading one-loop approximation in the double $(\varepsilon, y)$ expansion scheme, where $\varepsilon$ is a deviation from the upper critical dimension $d_c = 4$ and $y$ describes a scaling properties of the velocity ensemble. Altogether five distinct universality classes are expected to be macroscopically observable. In contrast to the incompressible case, we found that compressibility leads to an enhancement and stabilization of non-trivial asymptotic regimes.