Third-order perturbation analysis for p- and d-wave pairing states in two-dimensional repulsive Hubbard model

2002 ◽  
Vol 63 (6-8) ◽  
pp. 1435-1438
Author(s):  
Hirono Fukazawa ◽  
Kosaku Yamada
Keyword(s):  
Hubbard Model ◽  
Perturbation Analysis ◽  
Order Perturbation ◽  
Two Dimensional ◽  
Third Order ◽  
Wave Pairing ◽  
D Wave

Comparison of Numerical and Perturbation Solutions of Two-Dimensional Nonlinear Water-Wave Problems

1976 ◽  
Vol 20 (03) ◽  
pp. 160-170
Author(s):  
Nils Salvesen ◽  
C. von Kerczek
Keyword(s):  
Perturbation Theory ◽  
Numerical Solutions ◽  
Order Perturbation ◽  
Order Perturbation Theory ◽  
Wave System ◽  
Two Dimensional ◽  
Third Order ◽  
Flow Past ◽  
Wave Problems ◽  
Good Agreement

Numerical solutions of the nonlinear problem of the steady two-dimensional potential flow past a submerged line vortex are obtained using the finite-difference iterative technique previously presented by the authors. These solutions are compared in detail with third-order perturbation theory solutions. It is found that very good agreement is obtained for cases of positive circulation of the vortex with strength large enough to produce downstream waves whose steepness is within 15 percent of the maximum possible steepness of irrotational free waves. These computed waves are as steep as the steepest waves obtained in a certain experiment involving the flow past a two-dimensional hydrofoil. For negative circulation, there is substantial difference between the numerical results and third-order perturbation theory. The failure of the perturbation theory is discussed. Details of the far-downstream wave system obtained by the numerical method are compared with other numerical solutions and very high-order perturbation theory solutions of the free-wave problem. Very good agreement is obtained in most cases.

scholarly journals Plaquette versus ordinary d -wave pairing in the t′ -Hubbard model on a width-4 cylinder

2020 ◽  
Vol 102 (4) ◽  
Author(s):  
Chia-Min Chung ◽  
Mingpu Qin ◽  
Shiwei Zhang ◽  
Ulrich Schollwöck ◽  
Steven R. White ◽  
...  
Keyword(s):  
Hubbard Model ◽  
Wave Pairing ◽  
D Wave

scholarly journals CRITICAL CURRENT IN THE HIGH-Tc GLASS MODEL

1999 ◽  
Vol 10 (07) ◽  
pp. 1335-1345
Author(s):  
I. MORGENSTERN ◽  
W. FETTES ◽  
T. HUSSLEIN
Keyword(s):  
Hubbard Model ◽  
Critical Current ◽  
Critical Currents ◽  
Microscopic Description ◽  
High Tc ◽  
Wave Pairing ◽  
Glass Model ◽  
Current Densities ◽  
D Wave

The high-Tc glass model can be combined with the repulsive tt'–Hubbard model as microscopic description of the striped domains found in the high-Tc materials. In this picture, the finite Hubbard clusters are the origin of the d-wave pairing. In this paper we show that the glass model can also explain the critical currents usually observed in the high-Tc materials. We use two different approaches to calculate the critical current densities of the high-Tc glass model. Both lead to a strongly anisotropic critical current. Finally we give an explanation of why we nonetheless expect a nearly perfect isotropic critical current in high-Tc superconductors.

scholarly journals Phonons andd-wave pairing in the two-dimensional Hubbard model

2007 ◽  
Vol 75 (1) ◽  
Author(s):  
Carsten Honerkamp ◽  
Henry C. Fu ◽  
Dung-Hai Lee
Keyword(s):  
Hubbard Model ◽  
Two Dimensional ◽  
Wave Pairing

Correlation Effects of Third-order Perturbation in the Extended Hubbard Model

1989 ◽  
Vol 42 (5) ◽  
pp. 565
Author(s):  
CZ Wei ◽  
HQ Nie ◽  
L Li ◽  
KY Zhang
Keyword(s):  
Hubbard Model ◽  
Electron Correlation ◽  
Spin Correlation ◽  
Order Perturbation ◽  
Atomic Electron ◽  
Nearest Neighbour ◽  
Extended Hubbard Model ◽  
Third Order ◽  
The Third ◽  
Significant Correction

Using the local approach, we have performed a third�order perturbation calculation to investigate the effects of intra-atomic electron correlation and electron and spin correlation between nearest neighbour sites in the extended Hubbard model. We found that significant correction of the third order over the second order results and, in comparison with the results of the third-order perturbation where only the intra-atomic electron correlation is included, the influence of the electron and spin correlation between nearest neighbour sites on the correlation energy is non-negligible.

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 s- or d-wave pairing in the Hubbard model

1997 ◽  
Vol 282-287 ◽  
pp. 1703-1704 ◽  
Author(s):  
Y.M. Malozovsky ◽  
J.D. Fan
Keyword(s):  
Hubbard Model ◽  
Wave Pairing ◽  
D Wave
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