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Zeitschriftenartikel:

M. Ganahl, P. Thunström, F. Verstraete, K. Held, H.G. Evertz:
"Chebyshev expansion for impurity models using matrix product states";
Physical Review B, 90 (2014), 045144.



Kurzfassung englisch:
We improve a recently developed expansion technique for calculating real frequency spectral
functions of any one-dimensional model with short-range interactions, by postprocessing computed
Chebyshev moments with linear prediction. This can be achieved at virtually no cost and, in
sharp contrast to existing methods based on the dampening of the moments, improves the spectral
resolution rather than lowering it. We validate the method for the exactly solvable resonating level
model and the single impurity Anderson model. It is capable of resolving sharp Kondo resonances, as
well as peaks within the Hubbard bands when employed as an impurity solver for dynamical mean-
eld theory (DMFT). Our method works at zero temperature and allows for arbitrary discretization
of the bath spectrum. It achieves similar precision as the dynamical density matrix renormalization
group (DDMRG), at lower cost. We also propose an alternative expansion, of 1􀀀exp(􀀀 H) instead
of the usual H, which opens the possibility of using established methods for the time evolution of
matrix product states to calculate spectral functions directly.


"Offizielle" elektronische Version der Publikation (entsprechend ihrem Digital Object Identifier - DOI)
http://dx.doi.org/10.1103/PhysRevB.90.045144


Erstellt aus der Publikationsdatenbank der Technischen Universität Wien.