# The Hubbard Model in the Two-Pole Approximation

@article{Avella1998TheHM, title={The Hubbard Model in the Two-Pole Approximation}, author={Adolfo Avella and Ferdinando Mancini and Dario Villani and Liudmila Siurakshina and V.Yu. Yushankhai Universita' di Salerno and Joint Institute for Nuclear Research}, journal={International Journal of Modern Physics B}, year={1998}, volume={12}, pages={81-97} }

The two-dimensional Hubbard model is analyzed in the framework of the two-pole expansion. It is demonstrated that several theoretical approaches, when considered at their lowest level, are all equivalent and share the property of satisfying the conservation of the first four spectral momenta. It emerges that the various methods differ only in the way of fixing the internal parameters and that it exists a unique way to preserve simultaneously the Pauli principle and the particle–hole symmetry. A…

## 29 Citations

Bosonic sector of the two-dimensional Hubbard model studied within a two-pole approximation

- Physics
- 2003

The charge and spin dynamics of the two-dimensional Hubbard model in the paramagnetic phase is first studied by means of the two-pole approximation within the framework of the composite operator…

The Hubbard model beyond the two-pole approximation: a composite operator method study

- Physics
- 2014

Within the framework of the Composite Operator Method, a three-pole solution for the two-dimensional Hubbard model is presented and analyzed in detail. In addition to the two Hubbard operators, the…

NEW COMPARISONS FOR LOCAL QUANTITIES OF THE TWO-DIMENSIONAL HUBBARD MODEL

- Physics
- 2003

We have compared the results of out approximation scheme, the composite operator, method, for the double occupancy and the internal energy of the two-dimensional Hubbard model with numerical data…

Superconductivity in a two dimensional extended Hubbard model

- Physics
- 2005

Abstract.The Roth’s two-pole approximation has been used by the present authors
to investigate the role of d-p hybridization in the superconducting
properties of an extended d-p Hubbard model.…

COM(3p) Solution of the 2D Hubbard Model: Momentum-Resolved Quantities

- Physics
- 2014

Recently, within the framework of the composite operator method, it has been proposed that a three-pole solution for the two-dimensional Hubbard model (Eur. Phys. J. B 87, 45 (2014)),which is still…

The Hubbard model within the equations of motion approach

- Physics
- 2004

The Hubbard model plays a special role in condensed matter theory as it is considered to be the simplest Hamiltonian model one can write in order to describe anomalous physical properties of some…

Antiferromagnetic phase in the Hubbard model by means of the composite operator method

- Physics
- 2001

We have investigated the antiferromagnetic phase of two-dimensional (2D), three-dimensional (3D), and extended Hubbard models on a bipartite cubic lattice by means of the composite operator method…

## References

SHOWING 1-10 OF 33 REFERENCES

Perturbational approach to the one particle properties of the Hubbard model

- Physics
- 1990

It is shown that the Hubbard model can be viewed as limiting case of a periodic Anderson model. This relation is used to set up a perturbation theory for the Hubbard model with the…

Hubbard model in infinite dimensions.

- PhysicsPhysical review. B, Condensed matter
- 1992

We present an exact mapping of the Hubbard model in infinite dimensions onto a single-impurity Anderson (or Wolff) model supplemented by a self-consistency condition. This provides a mean-field…

Single-particle spectral density of the Hubbard model.

- PhysicsPhysical review. B, Condensed matter
- 1995

It is shown that the present approximation is capable of reproducing essential properties of the single-particle spectral function, and the two-pole spectrum is characterized by a direct gap, in agreement with the exact spectrum.

New functional integral approach to strongly correlated Fermi systems: The Gutzwiller approximation as a saddle point.

- PhysicsPhysical review letters
- 1986

This approach uncovers the limitations of the Gutzwiller approximation and clarifies its connection to the "auxiliary-boson" mean- field theory of the Anderson model, leading to a novel strong-coupling mean-field theory which allows for a unified treatment of antiferromagnetism and ferromagnets, metal-to-insulator transition, and Kondo compensation effects.

Physical properties of the half-filled Hubbard model in infinite dimensions.

- PhysicsPhysical review. B, Condensed matter
- 1993

A detailed quantitative study of the physical properties of the infinite-dimensional Hubbard model at half filling using an exact mapping onto a single-impurity model supplemented by a self-consistency condition is presented.

Correlated Lattice Fermions in High Dimensions

- Physics
- 1989

A new approach to correlated Fermi systems such as the Hubbard model, the periodic Anderson model etc. is discussed, which makes use of the limit of high spatial dimensions. This limit — which is…

Two-Dimensional Hubbard Model –Metal Insulator Transition Studied by Monte Carlo Calculation–

- Physics
- 1992

The Hubbard model on a square lattice in the ground state is investigated. Various aspects of Mott transition at half-filling are clarified from the quantum Monte Carlo study. Critical exponents of…

Spectral properties of the Anderson model

- Physics
- 1983

An investigation of the one particle spectrum of the (impurity-) Anderson model within the time ordered perturbation approach is presented. The approximation used includes all processes without…