A Gauge-Invariant Reorganization of Thermal Gauge Theory

Understand

This dissertation is devoted to the study of thermodynamics for quantum gauge theories.

• The poor convergence of quantum field theory at finite temperature has been the main obstacle in the practical applications of thermal QCD for decades.
• In this dissertation I apply hard-thermal-loop perturbation theory, which is a gauge-invariant reorganization of the conventional perturbative expansion for quantum gauge theories to the thermodynamics of QED and Yang-Mills theory to three-loop order.
• For the Abelian case, I present a calculation of the free energy of a hot gas of electrons and photons by expanding in a power series in $m_D/T$, $m_f/T$ and $e^2$, where $m_D$ and $m_f$ are the photon and electron thermal masses, respectively, and $e$ is the coupling constant.