Abstract
It is shown that finite-temperature calculations in field theory are manifestly Lorentz covariant at all stages if the Minkowski-space form of the temperature-dependent propagators is used and if the four-velocity of the heat bath is taken into account. New tensor structures involving generally arise but are severely constrained by covariant current conservation. A complete high-temperature () expansion of the vacuum polarization tensor for non-Abelian gauge theories is computed to order and displays the separate dependence on frequency and wave number that occurs at finite temperature. A covariant phenomenology of "electric" and "magnetic" properties is applied to the collective plasma effects, characterized by a plasma frequency for with fermions. The longitudinal normal modes of the "electric" field exist only for ; for all "electric" fields are screened. The transverse normal modes are plane waves along for ; for both transverse "electric" and "magnetic" fields are shielded except for the static () case.
- Received 15 March 1982
DOI:https://doi.org/10.1103/PhysRevD.26.1394
©1982 American Physical Society