Physics – Condensed Matter – Strongly Correlated Electrons
Scientific paper
1998-10-05
Physics
Condensed Matter
Strongly Correlated Electrons
3 pages, RevTex, N(k,k^{'}) is given explicitly
Scientific paper
In this article, we revisit the question of the validity of Hartree-Fock and random-phase approximations. We show that there is a connection between the two and while the RPA as it is known in much of the physics literature is of limited validity, there is a generalised sense in which the random phase approximation is of much wider applicability including to systems that do not possess Fermi surfaces. The main conclusion is that the Hartree-Fock approximation is a mean-field idea applied to the density operator, and the random-phase approximation is a mean-field idea applied to the number operator. The generalised RPA is used to compute single-particle properties such as momentum distribution and spectral functions. It is found that we have to go beyond the generalised RPA and include fluctuations in the momentum distribution in order to recover a nonzero imaginary part of the one-particle self energy, which is also explicitly computed, all this in any number of spatial dimensions and no bosonization is needed.
Chang Yia-Chung
Setlur Girish S.
No associations
LandOfFree
Exact Single-Particle Green Functions of Fermi Systems Without Using Bosonization or Are Hartree-Fock and Random Phase Approximations 'Controlled Approximations' ? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Exact Single-Particle Green Functions of Fermi Systems Without Using Bosonization or Are Hartree-Fock and Random Phase Approximations 'Controlled Approximations' ?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Exact Single-Particle Green Functions of Fermi Systems Without Using Bosonization or Are Hartree-Fock and Random Phase Approximations 'Controlled Approximations' ? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-638815