Dissertation > Mathematical sciences and chemical > Physics > Theoretical Physics > Thermodynamics and Statistical Physics > Statistical physics

BCS-BEC crossover region captivity Fermi cohesion body ground state and the excitation spectrum of theoretical studies

Author WangChengTao
Tutor MaYongLi
School Fudan University
Course Theoretical Physics
Keywords The imprisoned Fermi condensates BCS-BEC Crossover Generalized BdG equations
CLC O414.2
Type Master's thesis
Year 2008
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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 .

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