| Authors: |
A. Anfossi
and A. Montorsi
and C. Degli Esposti Boschi
|
| Editors: |
Luciano Pietronero
and Vittorio Loreto
and Stefano Zapperi
|
| URL: |
http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=38 |
| Tags: |
dmrg
entanglement
extended
hubbard
luther-emery
models
phase
quantum
statphys23
topic-8
transitions
|
| Abstract: |
We determine the quantum phase diagram of the one-dimensional Hubbard model with bond-charge interaction $X$ (Hirsch model) in addition to the usual Coulomb repulsion $U$ at half-filling and $T=0$ [1-2]. Such an extension is quite natural since the charge in the bond affects both screening and the effective potential acting on valence electrons; therefore the Wannier orbitals and the hopping between them should vary with the charge. The Hirsch model had been studied, in two dimensions, in the context of hole superconductivity [3], while a modified version of it has been derived as an effective model for the cuprates and shows enhanced $d$-wave superconducting correlations [4]. Moreover, recently it has been paramount to broader audiences and its relevance has been discussed in the context of mesoscopic transport [5] and quantum information [6] in one dimensional systems.
By means of the density-matrix renormalization group algorithm the charge gap closure is examined by both standard finite-size scaling analysis and looking at singularities in the derivatives of single-site entanglement. The results of the two techniques show that a quantum phase transition takes place (at a finite Coulomb interaction $u_{c}(x)$ for $x\ge 0.5$). The novel Luther-Emery phase is characterized by dominant incommensurate singlet-superconducting correlations at large distances, the incommensurability showing up in the spin and density structure factors. Furthermore, we find that inside the insulating phase there is a spin transition, separating the expected spin-density wave phase from a spontaneously dimerized bond-ordered wave one (fully gapped phase), the quantum phase transition being of Kosterlitz-Thouless type.
References:\\
1) A. Anfossi, C. Degli Esposti Boschi, A. Montorsi, and F. Ortolani, Phys. Rev. B 73, 085113 (2006).\\
2) A. Anfossi, C. Degli Esposti Boschi, A. Montorsi, F. Ortolani, A. A. Aligia, L. Arrachea, A. O. Dobry, C. Gazza, M. E. Torio, \textit{Incommensurability and unconventional superconductor to insulator transition in the Hubbard model with bond-charge interaction}, preprint march 2007\\
3) J. E. Hirsch, Physica C 158, 326 (1989); J. E. Hirsch and F. Marsiglio, Phys. Rev. B 39, 11515 (1989).\\
4) L. Arrachea and A. A. Aligia, Phys. Rev. B 59, 1333 (1999);
ibid 61, 9686 (2000).\\
5) A. Hubsch \emph{et al}, Phys. Rev. Lett. 96, 196401 (2006).\\
6) A. Anfossi, P. Giorda, A. Montorsi, and F. Traversa, Phys. Rev. Lett. 95, 056402 (2005); A. Anfossi, P. Giorda, and A. Montorsi, Phys. Rev. B 75, in production (2007). |
@incollection{statphys23_0038,
title = {Entangelement and quantum phase diagram of the bond-charge extended Hubbard model},
address = {Genova, Italy},
author = {A. Anfossi and A. Montorsi and C. Degli Esposti Boschi},
booktitle = {Abstract Book of the XXIII IUPAP International Conference on Statistical Physics},
editor = {Luciano Pietronero and Vittorio Loreto and Stefano Zapperi},
month = {9-13 July},
url = {http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=38},
year = {2007},
abstract = {We determine the quantum phase diagram of the one-dimensional Hubbard model with bond-charge interaction $X$ (Hirsch model) in addition to the usual Coulomb repulsion $U$ at half-filling and $T=0$ [1-2]. Such an extension is quite natural since the charge in the bond affects both screening and the effective potential acting on valence electrons; therefore the Wannier orbitals and the hopping between them should vary with the charge. The Hirsch model had been studied, in two dimensions, in the context of hole superconductivity [3], while a modified version of it has been derived as an effective model for the cuprates and shows enhanced $d$-wave superconducting correlations [4]. Moreover, recently it has been paramount to broader audiences and its relevance has been discussed in the context of mesoscopic transport [5] and quantum information [6] in one dimensional systems.
By means of the density-matrix renormalization group algorithm the charge gap closure is examined by both standard finite-size scaling analysis and looking at singularities in the derivatives of single-site entanglement. The results of the two techniques show that a quantum phase transition takes place (at a finite Coulomb interaction $u_{c}(x)$ for $x\ge 0.5$). The novel Luther-Emery phase is characterized by dominant incommensurate singlet-superconducting correlations at large distances, the incommensurability showing up in the spin and density structure factors. Furthermore, we find that inside the insulating phase there is a spin transition, separating the expected spin-density wave phase from a spontaneously dimerized bond-ordered wave one (fully gapped phase), the quantum phase transition being of Kosterlitz-Thouless type.
References:\\
1) A. Anfossi, C. Degli Esposti Boschi, A. Montorsi, and F. Ortolani, Phys. Rev. B 73, 085113 (2006).\\
2) A. Anfossi, C. Degli Esposti Boschi, A. Montorsi, F. Ortolani, A. A. Aligia, L. Arrachea, A. O. Dobry, C. Gazza, M. E. Torio, \textit{Incommensurability and unconventional superconductor to insulator transition in the Hubbard model with bond-charge interaction}, preprint march 2007\\
3) J. E. Hirsch, Physica C 158, 326 (1989); J. E. Hirsch and F. Marsiglio, Phys. Rev. B 39, 11515 (1989).\\
4) L. Arrachea and A. A. Aligia, Phys. Rev. B 59, 1333 (1999);
ibid 61, 9686 (2000).\\
5) A. Hubsch \emph{et al}, Phys. Rev. Lett. 96, 196401 (2006).\\
6) A. Anfossi, P. Giorda, A. Montorsi, and F. Traversa, Phys. Rev. Lett. 95, 056402 (2005); A. Anfossi, P. Giorda, and A. Montorsi, Phys. Rev. B 75, in production (2007).},
keywords = {dmrg entanglement extended hubbard luther-emery models phase quantum statphys23 topic-8 transitions }
}
::