Parquet theory of finite temperature boson systems

Abstract

In this dissertation, we use the parquet summation for the two-body vertex as the framework for a perturbation theory of finite-temperature homogeneous boson systems. Our present formalism is a first step toward a full description of the thermodynamic behavior of a finite temperature boson system through parquet summation. The current approximation scheme focuses on a system below the Bose-Einstein condensation temperature and considers only the contribution from Bogoliubov excitations out of a boson condensate. Comparison with the finite temperature variational theory by Campbell et al [1] shows strong similarities between variational theory and our current theory. Numerical results from a 4He system and a nuclear system are discussed.