Real-Time Thermal Ward-Takahashi Identity for Vectorial Current in QED and QCD
It is shown that by means of canonical operator approach the Ward-Takahashi identity (WTI) at finite temperature T and finite chemical potential μ for complete vectorial vertex and complete fermion propagator can be simply proven, rigorously for Quantum Electrodynamics, and approximately for Quantum Chromodynamics, where the ghost effect in the fermion sector is neglected. The WTI shown in the real-time thermal matrix form will give definite thermal constraints on the imaginary part of inverse complete Feynman propagator including self-energy for fermion and will play an important role in relevant physical processes. When the above inverse propagator is assumed to be real, the thermal WTI will essentially be reduced to its form at T = μ = 0 thus one can use it in the latter's form. At this point,a practical example is indicated.
作 者： ZHOU Bang-Rong 作者单位： Department of Physics, Graduate School of the Chinese Academy of Sciences, Beijing 100039, China 刊 名： 理论物理通讯(英文版) ISTIC SCI 英文刊名： COMMUNICATIONS IN THEORETICAL PHYSICS 年，卷(期)： 2004 42(7) 分类号： 关键词： Ward-Takahashi identity vectorial vertex real-time thermal field theory QED QCD