Second-order self-energy of the Hubbard Hamiltonian: Absence of quasiparticle excitations near half-filling

1993 ◽  
Vol 48 (18) ◽  
pp. 13654-13660 ◽  
Author(s):  
J. Galán ◽  
J. A. Vergés ◽  
A. Martin-Rodero
Keyword(s):  
Second Order ◽  
Hubbard Hamiltonian ◽  
Self Energy ◽  
Half Filling ◽  
Quasiparticle Excitations

scholarly journals Second-Order Electron Self-Energy in Hydrogenlike Ions

1999 ◽  
Vol 83 (12) ◽  
pp. 2312-2315 ◽  
Author(s):  
Igor Goidenko ◽  
Leonti Labzowsky ◽  
Andrei Nefiodov ◽  
Günter Plunien ◽  
Gerhard Soff
Keyword(s):  
Second Order ◽  
Self Energy

Second-order self-energy for the Anderson model analytical results

1979 ◽  
Vol 91 (1) ◽  
pp. 355-360 ◽  
Author(s):  
J. Zieliński ◽  
B. Kozarzewski
Keyword(s):  
Anderson Model ◽  
Second Order ◽  
Self Energy ◽  
Analytical Results

ANISOTROPIC PSEUDOGAP IN THE HALF-FILLING TWO-DIMENSIONAL HUBBARD MODEL AT FINITE TEMPERATURE

2000 ◽  
Vol 14 (21) ◽  
pp. 2271-2286
Author(s):  
TAIICHIRO SAIKAWA ◽  
ALVARO FERRAZ
Keyword(s):  
Fermi Surface ◽  
Fermi Level ◽  
Hubbard Model ◽  
Spectral Function ◽  
Density Of States ◽  
Spin Fluctuation ◽  
The Self ◽  
Two Dimensional ◽  
Self Energy ◽  
Half Filling

We have studied the pseudogap formation in the single-particle spectra of the half-filling two-dimensional Hubbard model. Using a Green's function with the one-loop self-energy correction of the spin and charge fluctuations, we have numerically calculated the self-energy, the spectral function, and the density of states in the weak-coupling regime at finite temperatures. Pseudogap formations have been observed in both the density of states and the spectral function at the Fermi level. The pseudogap in the spectral function is explained by the non-Fermi-liquid-like nature of the self-energy. The anomalous behavior in the self-energy is caused by both the strong antiferromagnetic spin fluctuation and the nesting condition on the non-interacting Fermi surface. In the present approximation, we find a logarithmic singularity in the integrand of the self-energy imaginary part. The pseudogap in the spectral function is highly momentum dependent on the Fermi surface. This anisotropy of the pseudogap is produced by the flatness of the band dispersion around the saddle point rather than the nesting condition on the Fermi level.

Second-order self-energy–vacuum-polarization contributions to the Lamb shift in highly charged few-electron ions

1996 ◽  
Vol 54 (4) ◽  
pp. 2805-2813 ◽  
Author(s):  
Hans Persson ◽  
Ingvar Lindgren ◽  
Leonti N. Labzowsky ◽  
Günter Plunien ◽  
Thomas Beier ◽  
...  
Keyword(s):  
Lamb Shift ◽  
Vacuum Polarization ◽  
Second Order ◽  
Self Energy

Second order self-energy of the two-dimensional Hubbard model

1997 ◽  
Vol 103 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Stéphane Daul ◽  
Michael Dzierzawa
Keyword(s):  
Hubbard Model ◽  
Second Order ◽  
Two Dimensional ◽  
Self Energy

Counterterms for the second-order electron self-energy in bound-state QED

1998 ◽  
Vol 57 (5) ◽  
pp. 4038-4040 ◽  
Author(s):  
Leonti Labzowsky ◽  
Alexander Mitrushenkov ◽  
Valery Shelyuto ◽  
Gerhard Soff
Keyword(s):  
Bound State ◽  
Second Order ◽  
Self Energy ◽  
Bound State Qed

Second order loop after loop self-energy correction for few-electron multicharged ions

1995 ◽  
Vol 200 (1) ◽  
pp. 51-55 ◽  
Author(s):  
A. Mitrushenkov ◽  
L. Labzowsky ◽  
I. Lindgren ◽  
H. Persson ◽  
S. Salomonson
Keyword(s):  
Second Order ◽  
Energy Correction ◽  
Self Energy
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