Perturbation Expansion for a Fermi Superfluid. I. Basic Formalism and Angular Momentum
Perturbation Expansion for a Fermi Superfluid. I. Basic Formalism and Angular Momentum
复制标题
费米超流体的微扰展开。
DOI：
10.1143/jpsj.65.1355
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发表时间：
1996
影响因子：
1.7
通讯作者：
T. Kita
中科院分区：
文献类型：
--
作者：
T. Kita
基于组态空间的凝聚波函数，建立了费米超流体理论。首先，从波函数中提取了两个基本成分，即有效凝聚波函数v(x1，x2)和准粒子场γ(X)，其中x表示空间坐标和自旋坐标rα。在将哈密顿量变换为γ的正态有序积之后，对于热力学势Ω和单粒子密度矩阵ρ，都得到了关于准粒子相互作用的微扰展开式。由此得到的热力学势包括以v→0为极限的Luttinger和Ward的正常态表达式。密度矩阵被写为相干部分ρ(C)和准粒子部分ρ(Q)的和，其中ρ(C)仅关于v(x1，x2)表示。结果表明，v和γ分别对共格性质和热力学性质起作用。因此，目前的形式主义为两个概念的形成提供了微观基础。
A theory of a Fermi superfluid is formulated based on the condensate wave function of the configuration space. First, two basic ingredients are extracted from the wave function, i.e. the effective condensate wave function v ( x 1 , x 2 ) and the quasiparticle field γ( x ) with x denoting the space and spin coordinates r α. After transforming a Hamiltonian into a normal-ordered product of γ, a perturbation expansion with respect to the quasiparticle interaction is formulated for both the thermodynamic potential Ω and the one-particle density matrix ρ. The thermodynamic potential thus obtained includes the normal-state expression of Luttinger and Ward as the limit of v → 0. The density matrix is written as a sum of the coherent part ρ ( c) and the quasiparticle part ρ ( q) , where ρ ( c) is expressed only with respect to v ( x 1 , x 2 ). It is shown that v and γ are responsible for the coherent and thermodynamic properties respectively. Thus the present formalism gives a microscopic foundation for the two-f...