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.