scholarly journals Self-consistent random phase approximation: Application to the Hubbard model for finite number of sites

2005 ◽  
Vol 71 (8) ◽  
Author(s):  
Mohsen Jemaï ◽  
Peter Schuck ◽  
Jorge Dukelsky ◽  
Raouf Bennaceur
Keyword(s):  
Finite Number ◽  
Hubbard Model ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Phase Approximation ◽  
Self Consistent

SELF-CONSISTENT T-MATRIX APPROXIMATION TO THE HUBBARD MODEL FOR A FINITE NUMBER OF SITES

2009 ◽  
Vol 23 (16) ◽  
pp. 2049-2062
Author(s):  
MOHSEN JEMAÏ
Keyword(s):  
Finite Number ◽  
Hubbard Model ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Fermi Gas ◽  
Phase Approximation ◽  
Matrix Approximation ◽  
Numerical Effort ◽  
Self Consistent ◽  
T Matrix

Within the 1D Hubbard model, linear closed chains with various numbers of sites are considered in particle–particle self-consistent random phase approximation (SCRPA) for the T-matrix. Encouraging results with a minimal numerical effort are obtained, confirming earlier results with this theory for other models. SCRPA solves the two-site problem exactly. It therefore contains the two electrons and high density Fermi gas limits correctly.

THE NUMBER SELF-CONSISTENT RENORMALIZED RANDOM PHASE APPROXIMATION

2006 ◽  
Vol 20 (30n31) ◽  
pp. 5334-5337
Author(s):  
A. MARIANO
Keyword(s):  
Charge Exchange ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Critical Value ◽  
Phase Approximation ◽  
Heavy Nuclei ◽  
Electromagnetic Transitions ◽  
Self Consistent ◽  
Eigen Values ◽  
Beta Decays

RPA and its quasiparticle generalization (QRPA) have been widely used to study electromagnetic transitions and beta decays in medium and heavy nuclei, being the pn-QRPA charge exchange mode extensively employed in the description of single and double beta decays in vibrational nuclei. However develops a collapse, i.e. it presents imaginary eigen-values for strengths beyond a critical value of the force. Extensions called renormalized QRPA (RQRPA) do not develop any collapse going beyond the simplest quasiboson approximation, however they present several drawbacks which will be analyzed.

Towards a self-consistent random-phase approximation for Fermi systems

1996 ◽  
Vol 54 (24) ◽  
pp. 17536-17546 ◽  
Author(s):  
F. Catara ◽  
G. Piccitto ◽  
M. Sambataro ◽  
N. Van Giai
Keyword(s):  
Random Phase Approximation ◽  
Random Phase ◽  
Phase Approximation ◽  
Fermi Systems ◽  
Self Consistent
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