The numerical simulation of quantum mechanical many-body systems by Monte Carlo Methods is in general only able to deliver ground-state or thermodynamical expectation values of physical observables. Recent developments however, made possible to perform an analytic continuation of imaginary-time quantum Monte Carlo data into real-frequency spectra. In particular the maximum-entropy method (MEM) was successfully applied to the Anderson impurity model and the Heisenberg quantum anti-ferromagnet both in one (1-D) and two (2-D) dimensions. We present here an application of the MEM on quantum Monte Carlo (QMC) simulations of the 1-D Hubbard model for large system sizes (N ≤ 84), such that the characterization of dispersion relations for excitation spectra becomes possible. The one-particle excitations posses cosine-like bands that, surprisingly, agree extremely well with slave-boson mean-field ones. Further comparisons with exact results from Bethe-Ansatz and conformai field-theory demonstrate the reliability of both the QMC simulations as well as the MEM.
|Titel||Computer Simulation Studies in Condensed-Matter Physics VII|
|Redakteure/-innen||David P. Landau, K. K. Mon, Professor Heinz-Bernd Schüttler Ph D|
|Herausgeber (Verlag)||Springer Berlin - Heidelberg|
|ISBN (Print)||978-3-642-79295-3 978-3-642-79293-9|
|Publikationsstatus||Veröffentlicht - 1994|
|Name||Springer Proceedings in Physics|
|Herausgeber (Verlag)||Springer Berlin Heidelberg|