Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Acta Physica Sinica

ELECTRON CORRELATION FUNCTIONS FOR NEUTRAL SOLITON

XU MIN-ZHONG, SUN XIN, (1)复旦大学物理系,上海200433; (2)中国科学院上海技术物理研究所红外物理国家重点实验室,上海200083

Published Jan 1, 1993• 0 citations
Publisher

Abstract

The electron correlation functions in spin-nondegenerate systems are studied in this paper. By using Hartree-Fock approximation, we present the spin-dependent electron correlation functions for neutral soliton, where there is only one up-spin electron on the mid-gap state. We obtain the pictures of spin-dependent correlation functions and discuss their properties.

DOI
10.7498/aps.42.1140

Related papers

ELECTRON CORRELATION FUNCTIONS FOR NEUTRAL SOLITON

Un X

The electron correlation functions in spin-nondegenerate systems are studied in this paper. By using Hartree-Fock approximation, we present the spin-dependent electron correlation functions for neutral soliton, where there is only one up-spin electron on the mid-gap state. We obtain the pictures of spin-dependent correlation functions and discuss their properties.

Acta Physica Sinica•Jan 1, 1993•0 citations

Solitons and Their Dynamics in One-Dimensional SDW Systems

Akira Terai, Yoshiyuki Ono

The dynamics of solitons in spin-density-wave systems is studied numerically using the one-dimensional Hubbard model. The motion of solitons is induced by an electric field, which is introduced into the model in the form of a time-dependent vector potential. The unrestricted Hartree-Fock approximation is used. An improved method of the decomposition of exponential operator is used to solve the time-dependent Hartree-Fock equation. First, the motion of a single soliton is studied, with emphasis on discrete lattice effects. It is found that the discreteness effects reduce the soliton saturation velocity which was found in a previous paper. Second, processes of collisions between a soliton and an antisoliton are studied. The states after the collision are quite different between the cases with a charge soliton pair and with a neutral soliton pair. In the case of the charged soliton pair, the solitons repel each other and reflect to opposite directions. In the case of the neutral soliton pair. In the case of the charged soliton pair, the solitons repel each other and reflect to opposite directions. In the case of the neutral soliton pair, the solitons attract each other to make a dynamical bound state.

Progress of Theoretical Physics Supplement•Jan 1, 1993•40 citations

Resonating Hartree-Fock Studies on Electron Correlation and Bond Alternation in the One Dimensional Half Filled Hubbard Model

Norikazu Tomita, Atsushi Ikawa, Hideo Fukutome

Effects of the on-site electron-electron Coulomb interaction U on bond alternation in the one dimensional half filled Hubbard model are studied by the resonating Hartree-Fock method. Two kinds of SDW neutral solitons S 0 A and S 0 B exist in a bond alternated lattice which are centered at a long bond and a short bond, respectively. S 0 A enhances but S 0 B suppresses the alternating bond order (ABO) due to bond alternation. Quantum fluctuations in the ground state involve more S 0 A 's than S 0 B 's because the former has lower energy than the latter with increasing bond alternation so that they enhance the ABO in the true ground state and consequently the bond alternation. The spin and singlet pair correlation functions show that electrons tend to make singlet pairs on nearest neighbor short bonds even from small U 's and small bond alternations.

Journal of the Physical Society of Japan•Dec 15, 1993•11 citations

Resonating Hartree-Fock Theory of the One Dimensional Hubbard Model. II. Breather Fluctuations in the Strong Correlation Regime

Shoji Yamamoto, Hideo Fukutome

The electronic structure of the strongly correlated one dimensional Hubbard model is calculated by the resonating Hartree-Fock (Res HF) method. In the strong correlation regime with the Coulomb repulsion U >∼6, SDW solitons localize almost on the central two sites and only one kind of neutral soliton pair has a much smaller energy than the other pairs. As quantum fluctuations in a periodic chain with 12 sites, we consider up to three diradical breathers consisting of the low energy neutral soliton pair. The Res HF ground state can explain 77.8% ( U =6) and 80.1% ( U =8) of the exact correlation energy. This is much better than the Gutzwiller method to use the SDW as the reference state that explains about 50% of the correlation energy. The breather fluctuations explain the rapid decreases in the short distance of the spin and staggered spin correlation functions. Other correlation functions and the excited states due to the quantum fluctuations are studied.

Journal of the Physical Society of Japan•Sep 15, 1992•9 citations

CORRELATION FUNCTIONS IN ONE-DIMENSIONAL LARGE-U HUBBARD MODEL: ZERO-FIELD AND FINITE-FIELD CASES

Hiroyuki Shiba, Masao Ogata

A recent study of the large-U limit of the one-dimensional (1D) Hubbard model is presented and discussed. It is pointed out first that the wave function has a simple structure in this limit. Namely, it is a product of Slater determinant of noninteracting spinless fermions and the wave function of 1D S=1/2 Heisenberg antiferromagnet. Secondly, by using this property, a direct calculation of momentum distribution and spin correlation function is carried out for the ground state at zero-field and finite-field cases. The results show various singularities exactly at the same position where one expects for the small-U case in both zero-field and finite-field cases. The critical exponents estimated from the size dependence are in reasonable agreement with those predicted by the Tomonaga-Luttinger-liquid and the conformal field theory.

International Journal of Modern Physics B•Jan 1, 1991•37 citations

Superconductivity in the two-dimensional Hubbard model: One-particle correlation functions

Chien-Hua Pao, N. E. Bickers

The one-particle correlation functions of a ${\mathit{d}}_{\mathit{x}}^{2}$-${\mathit{y}}^{2}$ superconducting state in the two-dimensional Hubbard model are investigated within the fluctuation-exchange approximation. This approximation has been previously applied to investigate properties of the Hubbard-model normal state, including incipient instabilities. Results are obtained for the wave vector and temperature dependence of the one-particle energy gap. A miximum gap ratio 2${\mathrm{\ensuremath{\Delta}}}_{\mathit{k}}^{\mathrm{max}}$(T=0)/${\mathit{k}}_{\mathit{B}}$${\mathit{T}}_{\mathit{c}}$ of order 10 is obtained for intermediate coupling strengths and electron densities near one per site. The potential appearance of spin excitons in two-particle response functions is discussed.

Physical review. B, Condensed matter•Jun 1, 1995•45 citations
The electron correlation functions in spin-nondegenerate systems are studied in this paper. By using Hartree-Fock approximation, we present the spin-dependent electron correlation functions for neutral soliton, where there is only one up-spin electron on the mid-gap state. We obtain the pictures of spin-dependent correlation functions and discuss their properties.
The dynamics of solitons in spin-density-wave systems is studied numerically using the one-dimensional Hubbard model. The motion of solitons is induced by an electric field, which is introduced into the model in the form of a time-dependent vector potential. The unrestricted Hartree-Fock approximation is used. An improved method of the decomposition of exponential operator is used to solve the time-dependent Hartree-Fock equation. First, the motion of a single soliton is studied, with emphasis on discrete lattice effects. It is found that the discreteness effects reduce the soliton saturation velocity which was found in a previous paper. Second, processes of collisions between a soliton and an antisoliton are studied. The states after the collision are quite different between the cases with a charge soliton pair and with a neutral soliton pair. In the case of the charged soliton pair, the solitons repel each other and reflect to opposite directions. In the case of the neutral soliton pair. In the case of the charged soliton pair, the solitons repel each other and reflect to opposite directions. In the case of the neutral soliton pair, the solitons attract each other to make a dynamical bound state.
Effects of the on-site electron-electron Coulomb interaction U on bond alternation in the one dimensional half filled Hubbard model are studied by the resonating Hartree-Fock method. Two kinds of SDW neutral solitons S 0 A and S 0 B exist in a bond alternated lattice which are centered at a long bond and a short bond, respectively. S 0 A enhances but S 0 B suppresses the alternating bond order (ABO) due to bond alternation. Quantum fluctuations in the ground state involve more S 0 A 's than S 0 B 's because the former has lower energy than the latter with increasing bond alternation so that they enhance the ABO in the true ground state and consequently the bond alternation. The spin and singlet pair correlation functions show that electrons tend to make singlet pairs on nearest neighbor short bonds even from small U 's and small bond alternations.
The electronic structure of the strongly correlated one dimensional Hubbard model is calculated by the resonating Hartree-Fock (Res HF) method. In the strong correlation regime with the Coulomb repulsion U >∼6, SDW solitons localize almost on the central two sites and only one kind of neutral soliton pair has a much smaller energy than the other pairs. As quantum fluctuations in a periodic chain with 12 sites, we consider up to three diradical breathers consisting of the low energy neutral soliton pair. The Res HF ground state can explain 77.8% ( U =6) and 80.1% ( U =8) of the exact correlation energy. This is much better than the Gutzwiller method to use the SDW as the reference state that explains about 50% of the correlation energy. The breather fluctuations explain the rapid decreases in the short distance of the spin and staggered spin correlation functions. Other correlation functions and the excited states due to the quantum fluctuations are studied.
A recent study of the large-U limit of the one-dimensional (1D) Hubbard model is presented and discussed. It is pointed out first that the wave function has a simple structure in this limit. Namely, it is a product of Slater determinant of noninteracting spinless fermions and the wave function of 1D S=1/2 Heisenberg antiferromagnet. Secondly, by using this property, a direct calculation of momentum distribution and spin correlation function is carried out for the ground state at zero-field and finite-field cases. The results show various singularities exactly at the same position where one expects for the small-U case in both zero-field and finite-field cases. The critical exponents estimated from the size dependence are in reasonable agreement with those predicted by the Tomonaga-Luttinger-liquid and the conformal field theory.
The one-particle correlation functions of a dx2{\mathit{d}}_{\mathit{x}}^{2}dx2​-y2{\mathit{y}}^{2}y2 superconducting state in the two-dimensional Hubbard model are investigated within the fluctuation-exchange approximation. This approximation has been previously applied to investigate properties of the Hubbard-model normal state, including incipient instabilities. Results are obtained for the wave vector and temperature dependence of the one-particle energy gap. A miximum gap ratio 2${\mathrm{\ensuremath{\Delta}}}_{\mathit{k}}^{\mathrm{max}}$(T=0)/kB{\mathit{k}}_{\mathit{B}}kB​Tc{\mathit{T}}_{\mathit{c}}Tc​ of order 10 is obtained for intermediate coupling strengths and electron densities near one per site. The potential appearance of spin excitons in two-particle response functions is discussed.