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arXiv · 1012.5543

Adaptive Lanczos-vector method for dynamic properties within the density-matrix renormalization group

P. E. Dargel·A. Honecker·R. Peters·R. M. Noack·T. Pruschke
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Abstract

Current widely-used approaches to calculate spectral functions using the density-matrix renormalization group in frequency space either necessarily include an artificial broadening (correction-vector method) or have limited resolution (time-domain density-matrix renormalization group with Fourier transform method). Here we propose an adaptive Lanczos-vector method to calculate the coefficients of a continued fraction expansion of the spectral function iteratively. We show that one can obtain a very accurate representation of the spectral function very efficiently, and that one can also directly extract the spectral weights and poles for the discrete system. As a test case, we study spinless fermions in one dimension and compare our approach to the correction vector method.

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P. E. Dargel, A. Honecker, R. Peters, R. M. Noack, T. Pruschke. 2011-04-13. Adaptive Lanczos-vector method for dynamic properties within the density-matrix renormalization group. https://doi.org/10.1103/physrevb.83.161104

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