We investigate the influence of different interaction strengths and dimerizations on the magnetization transport in antiferromagnetic spin 1/2 XXZ chains. We focus on the real-time evolution of the inhomogeneous initial state |upward arrow... upward arrow downward arrow... downward arrow > in using the adaptive time-dependent density-matrix renormalization group (adaptive t-DMRG). Time scales accessible to us are of the order of 100 units of time measured in Planck's/J for almost negligible error in the observables. We find ballistic magnetization transport for small S(z) S(z) interaction and arbitrary dimerization, but almost no transport for stronger S(z) S(z) interaction, with a sharp crossover at J(z) =1 . Additionally, we perform a detailed analysis of the error made by the adaptive time-dependent DMRG using the fact that the evolution in the XX model is known exactly. We find that the error at small times is dominated by the error made by the Trotter decomposition, whereas for longer times the DMRG truncation error becomes the most important, with a very sharp crossover at some "runaway" time. Overall, errors are extremely small before the "runaway" time.We investigate the influence of different interaction strengths and dimerizations on the magnetization transport in antiferromagnetic spin 1/2 XXZ chains. We focus on the real-time evolution of the inhomogeneous initial state |upward arrow... upward arrow downward arrow... downward arrow > in using the adaptive time-dependent density-matrix renormalization group (adaptive t-DMRG). Time scales accessible to us are of the order of 100 units of time measured in Planck's/J for almost negligible error in the observables. We find ballistic magnetization transport for small S(z) S(z) interaction and arbitrary dimerization, but almost no transport for stronger S(z) S(z) interaction, with a sharp crossover at J(z) =1 . Additionally, we perform a detailed analysis of the error made by the adaptive time-dependent DMRG using the fact that the evolution in the XX model is known exactly. We find that the error at small times is dominated by the error made by the Trotter decomposition, whereas for longer times the DMRG truncation error becomes the most important, with a very sharp crossover at some "runaway" time. Overall, errors are extremely small before the "runaway" time.

arXiv:cond-mat/0409692Physical Review EMar 3, 2005279 citations

Application of the DMRG technique to the Holstein model

Eric Jeckelmann, Steven R. White

APSMar 1, 19960 citations

Density-matrix renormalization-group method for excited states

Michael Chandross, J. Charles Hicks

The density-matrix renormalization-group (DMRG) method can provide approximate ground-state wave functions for many one-dimensional systems with a high degree of accuracy. Conventional DMRG techniques, however, cannot be expected to give accurate excited-state information because the excited states of interest are not explicitly included in the calculations. We discuss techniques for extending DMRG to accurately target and investigate arbitrary excited states. As an example we apply the method to investigate the properties of excitons within the extended Hubbard model. Our results show that excited-state calculations within the standard DMRG procedure give results that are quantitatively incorrect.The density-matrix renormalization-group (DMRG) method can provide approximate ground-state wave functions for many one-dimensional systems with a high degree of accuracy. Conventional DMRG techniques, however, cannot be expected to give accurate excited-state information because the excited states of interest are not explicitly included in the calculations. We discuss techniques for extending DMRG to accurately target and investigate arbitrary excited states. As an example we apply the method to investigate the properties of excitons within the extended Hubbard model. Our results show that excited-state calculations within the standard DMRG procedure give results that are quantitatively incorrect.

Physical review. B, Condensed matterApr 15, 199913 citations

Numerical renormalization-group study of the one-dimensionalt-Jmodel

Liang Chen, S. Moukouri

The one-dimensional t-J model is investigated using the density-matrix renormalization-group (DMRG) method. We report a generalization of the DMRG method to the case of arbitrary band filling and prove a theorem with respect to the reduced density matrix that accelerates the numerical computation. Lastly, using the extended DMRG method, we present the ground-state electron momentum distribution, as well as spin- and charge-correlation functions. The 3 ${\mathit{k}}_{\mathit{F}}$ anomaly of the momentum distribution function discussed by Ogata and Shiba is shown to disappear as J increases. We also argue that there exists a density-independent ${\mathit{J}}_{\mathit{c}}$ beyond which the system becomes an electron solid. \textcopyright{} 1996 The American Physical Society.The one-dimensional t-J model is investigated using the density-matrix renormalization-group (DMRG) method. We report a generalization of the DMRG method to the case of arbitrary band filling and prove a theorem with respect to the reduced density matrix that accelerates the numerical computation. Lastly, using the extended DMRG method, we present the ground-state electron momentum distribution, as well as spin- and charge-correlation functions. The 3${\mathit{k}}_{\mathit{F}}$ anomaly of the momentum distribution function discussed by Ogata and Shiba is shown to disappear as J increases. We also argue that there exists a density-independent ${\mathit{J}}_{\mathit{c}}$ beyond which the system becomes an electron solid. \textcopyright{} 1996 The American Physical Society.

arXiv:cond-mat/9510106Physical review. B, Condensed matterJan 15, 199612 citations

Generalized density dynamics

DAVID J. ROWE

Springer eBooksApr 6, 20080 citations

{\mathit{k}}_{\mathit{F}}

anomaly of the momentum distribution function discussed by Ogata and Shiba is shown to disappear as J increases. We also argue that there exists a density-independent

{\mathit{J}}_{\mathit{c}}

beyond which the system becomes an electron solid. \textcopyright{} 1996 The American Physical Society.