标题： 热规范理论中准粒子的寿命 显示英文标题

标题： Lifetime of quasiparticles in hot gauge theories

摘要： 带电激发态在超相对论等离子体中的微扰寿命计算受到红外发散的困扰，这些发散无法通过屏蔽修正消除。导致这些发散的物理过程是涉及长波长、准静态、磁胶子（或光子）交换的碰撞，这些胶子（或光子）不会被等离子体效应屏蔽。在QED中，主要的发散可以通过基于有限温度下Bloch-Nordsieck模型推广的非微扰处理进行重求和。得到的费米子传播子表达式没有红外问题，并在大时间尺度上表现出“非指数”阻尼：$S_R(t)\sim exp {-\alpha T t ln\omega_pt}$，其中$\omega_p=eT/3$是等离子体频率，$\alpha=e^2/4\pi$。 显示英文摘要

摘要： The perturbative calculation of the lifetime of charged excitations in ultrarelativistic plasmas is plagued with infrared divergences which are not eliminated by the screening corrections. The physical processes responsible for these divergences are the collisions involving the exchange of longwavelength, quasistatic, magnetic gluons (or photons), which are not screened by plasma effects. In QED, the leading divergences can be resummed in a non-perturbative treatement based on a generalization of the Bloch-Nordsieck model at finite temperature. The resulting expression of the fermion propagator is free of infrared problems, and exhibits a ``non-exponential'' damping at large times: $S_R(t)\sim exp {-\alpha T t ln\omega_pt}$, where $\omega_p=eT/3$ is the plasma frequency and $\alpha=e^2/4\pi$.