Quantum Electrodynamics at Finite Temperature: One-Loop Corrections to Electron Mass and Magnetic Moment

Employing the closed-time-path Green's function formalism (CTPGF), the electron self-energy and vertex function at finite temperature are derived at one-loop level. The so-called "double termn" does not appear in our approach and thus, the unitarity of the theory is ensured automatically. The temperature-dependent mass and vertex corrections are dispersive due to the existence of electron-positron pair background. In the nonrelativistic limit, the explicit forms of shifts due to temperature of both mass and Lande's $g$ factor are given, and their low temperature $(T \ll m)$ and high temperature $(T \gg m)$ limits are discussed.