Gravitational perturbations in a thermal environment

Author(s)

Fabiano Rabelo Machado

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Física (IF/SBI)
• Defense date: 2003-06-25

Examining board members

Fernando Tadeu Caldeira Brandt; Dionisio Bazeia Filho; Fernando Silveira Navarra; Adilson Jose da Silva; Alfredo Takashi Suzuki

• Advisor: Fernando Tadeu Caldeira Brandt

Abstract

We have computed the thermal one-graviton function and the self-energy in oneloop using a temporal gauge. In order to deal with the extra poles which are present in the temporal gauge, we employ an ambiguity-free technique in the imaginary-time formalismo We obtain, for temperatures T high compared with the externaI momentum and well below the Plank scale, the leading T4 as well as the sub-Ieading T2 and log(T) contributions to the graviton self-energy. We show that the extra pole contributions do not change the behaviour of the leading and sub-Ieading contributions from hard thermal loop region. We verify that the leading contributions are gauge independent. We also verify the t Hooft identities for the sub-Ieading T 2 terms and show that the logarithmic part has the same structure as the residue of ultraviolet pole of zero temperature graviton self-energy. We compute the dispersion relations up to GT2 order and we discuss the gauge dependence induced by sub-Ieading contributions T 2. We also compute the thermal one-graviton Green\'s function in the two-Ioop approximation for two distinct gauge classes. (AU)