scholarly journals Cluster-based mean-field and perturbative description of strongly correlated fermion systems: Application to the one- and two-dimensional Hubbard model

2015 ◽  
Vol 92 (8) ◽  
Author(s):  
Carlos A. Jiménez-Hoyos ◽  
Gustavo E. Scuseria
1989 ◽  
Vol 03 (12) ◽  
pp. 1833-1842
Author(s):  
P. Wölfle

We consider slave boson formulations of the Hubbard model, the t–J model and the Anderson model, in which spin and charge fermion degrees of freedom are represented by Bose fields. The approach has been applied to the Hubbard model generalizing the formulation of Kotliar and Ruckenstein. There the Gutzwiller solution is recovered as a saddle point. The method allows to find other types of mean field solutions in a systematic way. Dynamical correlation functions in mean field approximation as well as fluctuation contributions are also calculated.


2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Christopher Orthodoxou ◽  
Amelle Zaïr ◽  
George H. Booth

AbstractWith a combination of numerical methods, including quantum Monte Carlo, exact diagonalization, and a simplified dynamical mean-field model, we consider the attosecond charge dynamics of electrons induced by strong-field laser pulses in two-dimensional Mott insulators. The necessity to go beyond single-particle approaches in these strongly correlated systems has made the simulation of two-dimensional extended materials challenging, and we contrast their resulting high-harmonic emission with more widely studied one-dimensional analogues. As well as considering the photo-induced breakdown of the Mott insulating state and magnetic order, we also resolve the time and ultra-high-frequency domains of emission, which are used to characterize both the photo-transition, and the sub-cycle structure of the electron dynamics. This extends simulation capabilities and understanding of the photo-melting of these Mott insulators in two dimensions, at the frontier of attosecond non-equilibrium science of correlated materials.


2015 ◽  
Vol 10 (5) ◽  
Author(s):  
An Bao ◽  
Yao-Hua Chen ◽  
Heng-Fu Lin ◽  
Hai-Di Liu ◽  
Xiao-Zhong Zhang

2010 ◽  
Vol 24 (12n13) ◽  
pp. 1727-1755 ◽  
Author(s):  
Krzysztof Byczuk ◽  
Walter Hofstetter ◽  
Dieter Vollhardt

We review recent progress in our theoretical understanding of strongly correlated fermion systems in the presence of disorder. Results were obtained by the application of a powerful nonperturbative approach, the dynamical mean-field theory (DMFT), to interacting disordered lattice fermions. In particular, we demonstrate that DMFT combined with geometric averaging over disorder can capture Anderson localization and Mott insulating phases on the level of one-particle correlation functions. Results are presented for the ground state phase diagram of the Anderson–Hubbard model at half-filling, both in the paramagnetic phase and in the presence of antiferromagnetic order. We find a new antiferromagnetic metal which is stabilized by disorder. Possible realizations of these quantum phases with ultracold fermions in optical lattices are discussed.


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