scholarly journals Quasi-particle functional Renormalisation Group calculations in the two-dimensional half-filled Hubbard model at finite temperatures

2020 ◽  
Vol 9 (6) ◽  
Author(s):  
Daniel Rohe ◽  
Carsten Honerkamp
Keyword(s):  
Hubbard Model ◽  
Fermi Liquid ◽  
Renormalisation Group ◽  
Direct Access ◽  
Two Dimensional ◽  
Quasi Particle ◽  
Energy Data ◽  
Self Energy ◽  
Real Frequency

We present a highly parallelisable scheme for treating functional Renormalisation Group equations which incorporates a quasi-particle-based feedback on the flow and provides direct access to real-frequency self-energy data. This allows to map out the boundaries of Fermi-liquid regimes and to study the effect of quasi-particle degradation near Fermi liquid instabilities. As a first application, selected results for the two-dimensional half-filled perfectly nested Hubbard model are shown.

Fermi-liquid theory in the low-density two-dimensional Hubbard model

1993 ◽  
Vol 48 (14) ◽  
pp. 10567-10570 ◽  
Author(s):  
Sudhakar Yarlagadda ◽  
Susumu Kurihara
Keyword(s):  
Hubbard Model ◽  
Fermi Liquid ◽  
Low Density ◽  
Two Dimensional ◽  
Fermi Liquid Theory ◽  
Liquid Theory

Anomalous Fermi Liquid Effects in Two-Dimensional Hubbard Model near Half-Filling

2000 ◽  
Vol 69 (7) ◽  
pp. 2158-2163 ◽  
Author(s):  
Yuki Fuseya ◽  
Hideaki Maebashi ◽  
Satoshi Yotsuhashi ◽  
Kazumasa Miyake
Keyword(s):  
Hubbard Model ◽  
Fermi Liquid ◽  
Two Dimensional ◽  
Half Filling

RENORMALISATION GROUP ANALYSIS OF THE TWO-DIMENSIONAL HUBBARD MODEL: SPIN CORRELATIONS AND D-WAVE SUPERCONDUCTIVITY

2003 ◽  
Vol 17 (28) ◽  
pp. 5279-5288
Author(s):  
W. METZNER
Keyword(s):  
Hubbard Model ◽  
Spin Density ◽  
Density Wave ◽  
Group Analysis ◽  
Interaction Strength ◽  
Renormalisation Group ◽  
Model Parameters ◽  
Two Dimensional ◽  
Effective Interactions ◽  
D Wave

The repulsive two-dimensional Hubbard model is analysed within a functional renormalisation group (RG) approach. The flow equation for the effective interactions is evaluated on 1-loop level. The effective interactions diverge at a finite energy scale which is exponentially small for small bare interactions. To analyse the nature of the instabilities signalled by the diverging interactions, we compute the flow of the superconducting susceptibilities for various pairing symmetries and also charge and spin density susceptibilities. Depending on the choice of the model parameters (hopping amplitudes, interaction strength and band-filling) we find spin density wave instabilities or d-wave superconductivity as leading instability close to half-filling. This calculation establishes the existence of d-wave superconductivity in the Hubbard model beyond doubt.

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.

Crossover from Fermi liquid to Luttinger-liquid-like behavior in the two-dimensional Hubbard model

1993 ◽  
Vol 48 (5) ◽  
pp. 3527-3530 ◽  
Author(s):  
D. N. Aristov ◽  
S. V. Maleyev ◽  
A. G. Yashenkin
Keyword(s):  
Hubbard Model ◽  
Fermi Liquid ◽  
Luttinger Liquid ◽  
Two Dimensional

FUNCTIONAL RENORMALIZATION GROUP IN THE 2D HUBBARD MODEL

2006 ◽  
Vol 20 (19) ◽  
pp. 2636-2646 ◽  
Author(s):  
CARSTEN HONERKAMP
Keyword(s):  
Renormalization Group ◽  
Hubbard Model ◽  
Fermi Liquid ◽  
Broken Symmetry ◽  
Two Dimensional ◽  
Functional Renormalization Group ◽  
Recent Developments ◽  
Dimensional Models ◽  
Low Dimensional

We review recent developments in functional renormalization group (RG) methods for interacting fermions. These approaches aim at obtaining an unbiased picture of competing Fermi liquid instabilities in the low-dimensional models like the two-dimensional Hubbard model. We discuss how these instabilities can be approached from various sides and how the fermionic RG flow can be continued into phases with broken symmetry.

Sign in / Sign up

Export Citation Format

Share Document