scholarly journals Numerical renormalization-group approach to fluctuation exchange in the presence of electron-phonon coupling: Pairing in the Holstein-Hubbard model

1999 ◽  
Vol 60 (2) ◽  
pp. 1283-1295 ◽  
Author(s):  
C.-H. Pao ◽  
H.-B. Schüttler
Keyword(s):  
Renormalization Group ◽  
Hubbard Model ◽  
Phonon Coupling ◽  
Group Approach ◽  
Numerical Renormalization Group ◽  
Electron Phonon Coupling ◽  
Renormalization Group Approach

Wilson's Numerical Renormalization Group Calculation of the Anderson–Holstein Model: Phonon Propagator

2003 ◽  
Vol 17 (18n20) ◽  
pp. 3381-3386 ◽  
Author(s):  
Han-Yong Choi ◽  
Tae-Ho Park ◽  
Gun Sang Jeon
Keyword(s):  
Renormalization Group ◽  
Phonon Mode ◽  
Soft Mode ◽  
Coulomb Repulsion ◽  
Zero Temperature ◽  
Coupling Constant ◽  
Phonon Coupling ◽  
Improved Method ◽  
Numerical Renormalization Group ◽  
Electron Phonon Coupling

We study the symmetric Anderson–Holstein (AH) model at zero temperature with Wilson's numerical renormalization group (NRG) technique to study the interplay between the electron-electron and electron-phonon interactions. An improved method for calculating the phonon propagator using the NRG technique is presented and applied to the AH model as the onsite Coulomb repulsion U and electron-phonon coupling constant g are varied. As g is increased, the phonon propagator is successively renormalized, and for g≳gco crosses over to the regime where the mode splits into two components, one of which approaches back to the bare frequency and the other develops into a soft mode. The initial renormalization of the phonon mode, as g is increased from 0, can be either positive or negative depending on U and the hybridization Δ.

Sign in / Sign up

Export Citation Format

Share Document