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

First excited state calculation using different phonon bases for the two-site Holstein model

Jayita Chatterjee, A. N. Das

Published Jan 1, 2000• 0 citations
OpenAlex

Abstract

The single-electron energy and static charge-lattice deformation correlations have been calculated for the first excited state of a two-site Holstein model within perturbative expansions using different standard phonon bases obtained through Lang-Firsov (LF) transformation, LF with squeezed phonon states, modified LF, modified LF transformation with squeezed phonon states, and also within weak-coupling perturbation approach. Comparisons of the convergence of the perturbative expansions for different phonon bases reveal that modified LF approach works much better than other approaches for major range of the coupling strength.

Related papers

FIRST EXCITED STATE CALCULATION USING DIFFERENT PHONON BASES FOR THE TWO-SITE HOLSTEIN MODEL

JAYITA CHATTERJEE, A. N. Das

The single-electron energy and static charge-lattice deformation correlations have been calculated for the first excited state of a two-site Holstein model within perturbative expansions using different standard phonon bases obtained through Lang–Firsov (LF) transformation, LF with squeezed phonon states, modified LF, modified LF transformation with squeezed phonon states, and also within weak-coupling perturbation approach. Comparisons of the convergence of the perturbative expansions for different phonon bases reveal that modified LF approach works much better than other approaches for major range of the coupling strength.

arXiv:cond-mat/0003256•International Journal of Modern Physics B•Sep 30, 2000•0 citations

Comparison of perturbative expansions using different phonon bases for the two-site Holstein model

Jayita Chatterjee, A. N. Das

The two-site single-polaron problem is studied within perturbative expansions using different standard phonon bases obtained through Lang-Firsov (LF), modified LF, and modified LF transformations with squeezed phonon states. The role of these convergent expansions using the above prescriptions in lowering the energy and in determining the correlation functions are compared for different values of the coupling strength. The single-electron energy, oscillator wave functions, and correlation functions are calculated for the same system. The applicability of different phonon bases in different regimes of the coupling strength, as well as in different regimes of hopping, is also discussed.

arXiv:cond-mat/9908172•Physical review. B, Condensed matter•Feb 15, 2000•28 citations

Perturbative expansion using variational phonon basis for Holstein model

Jayita Chatterjee, A. N. Das, P. Choudhury

A simple variational displacement phonon basis, obtained through the modified Lang-Firsov (MLF) transformation, is proposed to study the Holstein model.This phonon basis contains only one variational parameter, but capable of describing lattice distortions at distant sites from the charge carrier. Perturbation method based on this MLF basis is employed to calculate the single-electron ground-state energy and static charge-lattice deformation correlation as a function of electron-phonon coupling. The energy obtained up to the second-order perturbation within this approach agrees well with the available numerical results for the entire range of coupling strength.

arXiv:cond-mat/0110308•Oct 16, 2001•0 citations

Two-site two-electron Holstein model: a perturbation study

Jayita Chatterjee, A. N. Das

The two-site two-electron Holstein model is studied within a perturbation method based on a variational phonon basis obtained through the modified Lang-Firsov (MLF) transformation. The ground-state wave function and the energy are found out considering up to the seventh and eighth order of perturbation, respectively. The convergence of the perturbation corrections of different orders to the ground state energy as well as to different correlation functions are investigated. The kinetic energy and the correlation functions involving charge and lattice deformations are studied as a function of electron-phonon ($e$-ph) coupling for different values of adiabaticity parameter and Coulomb repulsion. The simultaneous effect of the $e$-ph coupling and Coulomb repulsion on the kinetic energy shows interesting features.

arXiv:cond-mat/0210607•Oct 28, 2002•0 citations

Two-site polaron problem: a perturbation approach with variational basis states

A. N. Das, Jayita Chatterjee

A convergent perturbation method using modified Lang Firsov transformation is developed for a two-site single-polaron system. The method is applicable for the entire range of the electron-phonon coupling strength. The single-electron energies, oscillator wave functions and correlation functions, calculated using this method, are in good agreement with the exact results. 2

•Jan 1, 1999•13 citations

TWO-SITE POLARON PROBLEM: A PERTURBATION APPROACH WITH VARIATIONAL BASIS STATES

A. N. Das, JAYITA CHATTERJEE

A convergent perturbation method using modified Lang Firsov transformation is developed for a two-site single-polaron system. The method is applicable for the entire range of the electron–phonon coupling strength from the antiadiabatic limit to the intermediate region of hopping. The single-electron energies, oscillator wavefunctions and correlation functions, calculated using this method, are in good agreement with the exact results.

arXiv:cond-mat/9905373•International Journal of Modern Physics B•Dec 30, 1999•14 citations
The single-electron energy and static charge-lattice deformation correlations have been calculated for the first excited state of a two-site Holstein model within perturbative expansions using different standard phonon bases obtained through Lang-Firsov (LF) transformation, LF with squeezed phonon states, modified LF, modified LF transformation with squeezed phonon states, and also within weak-coupling perturbation approach. Comparisons of the convergence of the perturbative expansions for different phonon bases reveal that modified LF approach works much better than other approaches for major range of the coupling strength.
The single-electron energy and static charge-lattice deformation correlations have been calculated for the first excited state of a two-site Holstein model within perturbative expansions using different standard phonon bases obtained through Lang–Firsov (LF) transformation, LF with squeezed phonon states, modified LF, modified LF transformation with squeezed phonon states, and also within weak-coupling perturbation approach. Comparisons of the convergence of the perturbative expansions for different phonon bases reveal that modified LF approach works much better than other approaches for major range of the coupling strength.
The two-site single-polaron problem is studied within perturbative expansions using different standard phonon bases obtained through Lang-Firsov (LF), modified LF, and modified LF transformations with squeezed phonon states. The role of these convergent expansions using the above prescriptions in lowering the energy and in determining the correlation functions are compared for different values of the coupling strength. The single-electron energy, oscillator wave functions, and correlation functions are calculated for the same system. The applicability of different phonon bases in different regimes of the coupling strength, as well as in different regimes of hopping, is also discussed.
A simple variational displacement phonon basis, obtained through the modified Lang-Firsov (MLF) transformation, is proposed to study the Holstein model.This phonon basis contains only one variational parameter, but capable of describing lattice distortions at distant sites from the charge carrier. Perturbation method based on this MLF basis is employed to calculate the single-electron ground-state energy and static charge-lattice deformation correlation as a function of electron-phonon coupling. The energy obtained up to the second-order perturbation within this approach agrees well with the available numerical results for the entire range of coupling strength.
The two-site two-electron Holstein model is studied within a perturbation method based on a variational phonon basis obtained through the modified Lang-Firsov (MLF) transformation. The ground-state wave function and the energy are found out considering up to the seventh and eighth order of perturbation, respectively. The convergence of the perturbation corrections of different orders to the ground state energy as well as to different correlation functions are investigated. The kinetic energy and the correlation functions involving charge and lattice deformations are studied as a function of electron-phonon (eee-ph) coupling for different values of adiabaticity parameter and Coulomb repulsion. The simultaneous effect of the eee-ph coupling and Coulomb repulsion on the kinetic energy shows interesting features.