ANTIFERROMAGNETIC ORDERING IN THE HUBBARD MODEL: SLAVE BOSON APPROACH, PATH-INTEGRAL FORMULATION

The magnetic phase diagram (temperature versus doping) for the Hubbard model in the large U/t limit has been constructed by using the path-integral method. The antiferromagnetic order parameter has been represented in terms of fermion operators which correspond to neutral, spin one-half quasi-particles, spinons. Numerical calculations have been performed for the two-dimensional square lattice. A stable antiferromagnetic phase for the half-filled band has been found below a critical temperature TC=J where J=4t2/U is the superexchange interaction. It has been shown that antiferromagnetism is destroyed by doping with about 15% of holes for t/J=10. The results are discussed in the light of recent experiments for high TC oxides.

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ON ANTIFERROMAGNETIC INSTABILITY IN THE HUBBARD MODEL

International Journal of Modern Physics B ◽

10.1142/s021797928900107x ◽

1989 ◽

Vol 03 (11) ◽

pp. 1681-1690 ◽

Cited By ~ 2

Author(s):

PIOTR WRÓBEL ◽

TADEUSZ K. KOPEĆ

Keyword(s):

Hubbard Model ◽

Integral Method ◽

Order Parameter ◽

Magnetic Phase ◽

Magnetic Phase Diagram ◽

Functional Integral ◽

Square Lattice ◽

Antiferromagnetic Order ◽

Static Approximation ◽

Functional Integral Method

A functional integral method applied to the Hubbard model has been used to construct the magnetic phase diagram (temperature versus doping) for large U/t. The antiferromagnetic order parameter has been represented in terms of fermion operators which correspond to neutral, spin one-half quasi-particles i.e. spinons. Static approximation has been applied. Numerical calculations have been performed for the two-dimensional square lattice. A stable antiferromagnetic phase for the half-filled band has been found below the critical temperature TN=J where J=4t2/U is the superexchange interaction. It has been shown that antiferromagnetism is destroyed by doping with about 15% of holes for t/J=10. The results are discussed in the light of recent experiments for high Tc oxides.

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PATH-INTEGRAL FORMULATION OF CASIMIR EFFECTS IN SUPERSYMMETRIC QUANTUM ELECTRODYNAMICS

Modern Physics Letters A ◽

10.1142/s0217732399001097 ◽

1999 ◽

Vol 14 (16) ◽

pp. 1033-1042 ◽

Cited By ~ 4

Author(s):

HIROYUKI ABE ◽

JUNYA HASHIDA ◽

TAIZO MUTA ◽

AGUS PURWANTO

Keyword(s):

Boundary Condition ◽

Path Integral ◽

Quantum Electrodynamics ◽

Integral Method ◽

Mass Term ◽

Casimir Energy ◽

Mass Dependence ◽

Path Integral Formulation ◽

Suitable Boundary Condition ◽

Path Integral Method

The path-integral method of calculating the Casimir energy between two parallel conducting plates is developed within the framework of supersymmetric quantum electrodynamics at vanishing temperature as well as at finite temperature. The choice of the suitable boundary condition for the photino on the plates is argued and the physically acceptable condition is adopted which eventually breaks the supersymmetry. The photino mass term is introduced in the Lagrangian and the photino mass dependence of the Casimir energy and pressure is fully investigated.

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Path Integral Quantization of Regular Lagrangian

Applied Physics Research ◽

10.5539/apr.v10n1p9 ◽

2018 ◽

Vol 10 (1) ◽

pp. 9

Author(s):

Ola A. Jarabah

Keyword(s):

Phase Space ◽

Path Integral ◽

Integral Method ◽

Separation Of Variables ◽

Integral Formulation ◽

Path Integral Formulation ◽

Jacobi Function ◽

Path Integral Quantization ◽

Separation Of Variables Method ◽

Path Integral Method

Path integral formulation based on the canonical method is discussed. The Hamilton Jacobi function for regular Lagrangian is obtained using separation of variables method. This function is used to quantize regular systems using path integral method. The path integral is obtained as integration over the canonical phase space coordinates. One illustrative example is considered to demonstrate the application of our formalism.

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Local moments versus itinerant antiferromagnetism: Magnetic phase diagram and spectral properties of the anisotropic square lattice Hubbard model

Physical Review B ◽

10.1103/physrevb.103.125137 ◽

2021 ◽

Vol 103 (12) ◽

Author(s):

Marcin Raczkowski ◽

Fakher F. Assaad ◽

Masatoshi Imada

Keyword(s):

Phase Diagram ◽

Hubbard Model ◽

Spectral Properties ◽

Magnetic Phase ◽

Magnetic Phase Diagram ◽

Square Lattice ◽

Local Moments

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MAGNETIC ORDERING IN A TWO-DIMENSIONAL HUBBARD MODEL

Modern Physics Letters B ◽

10.1142/s0217984988000084 ◽

1988 ◽

Vol 02 (01) ◽

pp. 505-509

Author(s):

HUI-QUAN NIE ◽

BAO-HUA ZHAO ◽

KAI-YI ZHANG ◽

K.A. Chao ◽

R. MICNAS

Keyword(s):

Hubbard Model ◽

Magnetic Phase ◽

Three Dimensional ◽

Perturbation Expansion ◽

Magnetic Phase Diagram ◽

Magnetic Ordering ◽

Two Dimensional ◽

Antiferromagnetic Ordering ◽

Monte Carlo Investigation ◽

Magnetic Structure Factor

We have used the fourth order perturbation expansion to construct the magnetic phase diagram of the two-dimensional Hubbard model. To the contrary of the three-dimensional case, a stable antiferromagnetic phase is found at the limit of (t/U)≃0 if the electron density n lies in the region 0.95<n<1.05. Our results for n=0.9 are compared to the recent indecisive Monte-Carlo investigation on the magnetic structure factor regarding the antiferromagnetic ordering.

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