Publicação

Charge dynamics in half-filled hubbard chains with finite on-site interaction

Detalhes bibliográficos
Resumo:	We study the charge dynamic structure factor of the one-dimensional Hubbard model with finite on-site repulsion U at half-filling. Numerical results from the time-dependent density matrix renormalization group are analyzed by comparison with the exact spectrum of the model. The evolution of the line shape as a function of U is explained in terms of a relative transfer of spectral weight between the two-holon continuum that dominates in the limit U →∞ and a subset of the two-holon-two-spinon continuum that reconstructs the electron-hole continuum in the limit U → 0. Power-law singularities along boundary lines of the spectrum are described by effective impurity models that are explicitly invariant under spin and η-spin SU(2) rotations. The Mott-Hubbard metal-insulator transition is reflected in a discontinuous change of the exponents of edge singularities at U = 0. The sharp feature observed in the spectrum for momenta near the zone boundary is attributed to a van Hove singularity that persists as a consequence of integrability.
Autores principais:	Carmelo, José Manuel Pereira
Outros Autores:	Pereira, R. G.; Penc, K.; Sacramento, Pedro D.
Assunto:	Charge dynamics in half-filled hubbard chains
Ano:	2012
País:	Portugal
Tipo de documento:	artigo
Tipo de acesso:	acesso restrito
Instituição associada:	Universidade do Minho
Idioma:	inglês
Origem:	RepositóriUM - Universidade do Minho

Descrição
Resumo:	We study the charge dynamic structure factor of the one-dimensional Hubbard model with finite on-site repulsion U at half-filling. Numerical results from the time-dependent density matrix renormalization group are analyzed by comparison with the exact spectrum of the model. The evolution of the line shape as a function of U is explained in terms of a relative transfer of spectral weight between the two-holon continuum that dominates in the limit U →∞ and a subset of the two-holon-two-spinon continuum that reconstructs the electron-hole continuum in the limit U → 0. Power-law singularities along boundary lines of the spectrum are described by effective impurity models that are explicitly invariant under spin and η-spin SU(2) rotations. The Mott-Hubbard metal-insulator transition is reflected in a discontinuous change of the exponents of edge singularities at U = 0. The sharp feature observed in the spectrum for momenta near the zone boundary is attributed to a van Hove singularity that persists as a consequence of integrability.