Pauli Exchange Correlated Composite-Boson Condensation: A Many-Body Green's Function Approach

Abstract

In this research, we develop a many-body Green's function approach for interacting composite bosons in the Bose-Einstein condensed phase. The resummation scheme dealing with the carrier-carrier exchange between many-body composite bosons in cold condensation is manifested as a diagrammatic technique through the introduction of a set of Dyson equations for composite bosons. We diagrammatically calculate the specific heat capacity of neutral composite bosons, made of mass-imbalanced fermions with opposite charges, up to the first orders of the Pauli exchange and Coulomb interaction. Condensate phenomena due to the effect of the carrier-carrier exchange are discussed. In comparison with the approximation that composite bosons behave like interacting fundamental bosons, our result shows that the energy reduction from the carrier-carrier exchange stabilizes composite-boson condensates.