BCS-BEC crossover region captivity Fermi cohesion body ground state and the excitation spectrum of theoretical studies
|Keywords||The imprisoned Fermi condensates BCS-BEC Crossover Generalized BdG equations|
With the rapid development of the Feshbach resonance technology , the ultracold imprisoned Fermi condensates physicist who caused a great deal of interest in the BCS-BEC crossover region . Departure from the well-known BCS theory of superconductivity and BEC superfluid theory , has been substantially clear physical image of the system . The paper first reviews the progress of cross - regional studies of the BCS-BEC . A new equation of state and the ground state wave function satisfies the generalized Gross-Pitaevskii (GP) equation using variational method for solving nonlinear generalized GP equation , the ground state wave function and the chemical potential . Excited state system of generalized Bogoliubov-de Gennes (BdG) equations . The main method is to select a three-dimensional the axisymmetric harmonic oscillator wave functions for the basis vectors , expand the excited state wave function , generalized BdG equations into solving the generalized eigenvalue problem and by introducing the Pauli matrices , the solution of the question to make simple and easy solution . The characteristics of this paper is the analytical analysis of the ground state of the system , and the excited state by numerical calculation method . The equation of state and its multi- index , the chemical potential and the ground state wave function of the theoretical curves show the nature of the ground state of the system . Analytical calculation can not be related to the parameter range , the lower several spectroscopy numerical curve with the system parameter changes , and was found when comparing the results of the experiments and other methods , numerical results show that the system excited state of nature .