mean field theoryHubbard modelexact expressiongrand potentialWe derive an exact expression for the grand potential of the Hubbard model in d=u221e dimensions. By simplifying the energy transfer between up and down spins we obtain a comprehensive mean-field theory for this model. It is (i) ...
We summarize some of the results we have obtained in our recent studies of the Hubbard model on the square and triangular lattices using (1) spin-boson, slave-fermion mean field theories and (2) the Hartree-Fock mean field theory allowing for xy-SPIRAL spin order....
The recently introduced concept of exact mean-field theories is applied to the extended simplified Hubbard model, which is a one-band extended Hubbard model (including nearest-neighbor interaction) where only the ↓ electrons can hop. An exact mean-field Hamiltonian is derived for the model on a...
It is shown, for a small hole doping relative to half filling, that the large-U limit of the Hubbard model (or J=0 limit of the t-J model) exhibits an all-electron Peierls instability towards a state with a charge-density wave. The resulting gap in the spinon spectrum renders the mo...
Fabrizio, Quantum quenches in the Hubbard model: Time- dependent mean-field theory and the role of quantum fluctuations, Phys. Rev. B 83, 165105 (2011).M. Schiró and M. Fabrizio, Quantum Quenches in the Hubbard Model: Time-Dependent Mean-Field Theory and the Role of Quantum Fluctuations...
We develop a simple mean-field theory for studying spin-1 Bose-Hubbard model for cold atoms in an optical lattice model and obtain its zero temperature phase diagram. The superfluid phase can be polar (ferro) for antiferromagnetic (ferromagnetic) interaction. The superfluid to Mott insulator transi...
Mean-Field Theory 来自 Springer 喜欢 0 阅读量: 32 作者:NB Melnikov,BI Reser 摘要: This chapter is devoted to applications of the mean-field approximation in metals. We confine the presentation to the Hubbard model, which is relevant to the narrow-band metals. This way we avoid unnecessary ...
Using functional techniques, the Hubbard model consisting of self-coupled lattice fermions is transformed into a bosonic functional integral. In this form it is treated by a mean field approximation in its modern version as a systematic expansion around a saddle point. The method is generalized to...
We have generalized the dynamical mean-field theory to study the doping dependence of the crossover from antiferromagnetic to short-range order modelled by an incommensurate spin density wave in the Hubbard model. The local selfenergy which includes spin fluctuations gives quasiparticle weights and spec...
A new mean field theory is proposed for the Mott transition in the Hubbard model based on the slave rotor representation of the electron operator. This theory provides a better description of the role of the long range charge correlation in the Mott insulating state and offers a good estimation...