Die u:cris Detailansicht:

Chebyshev expansion for impurity models using matrix product states

Autor(en)
Martin Ganahl, Patrik Thunstroem, Frank Verstraete, Karsten Held, Hans Gerd Evertz
Abstrakt

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-field theory. 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, at lower cost. We also propose an alternative expansion, of 1−exp(−τH) instead of the usual H, which opens the possibility of using established methods for the time evolution of matrix product states to calculate the spectral functions directly.

Organisation(en)
Quantenoptik, Quantennanophysik und Quanteninformation
Externe Organisation(en)
Technische Universität Wien, Ghent University , Technische Universität Graz
Journal
Physical Review B
Band
90
Anzahl der Seiten
12
ISSN
1098-0121
DOI
https://doi.org/10.1103/PhysRevB.90.045144
Publikationsdatum
07-2014
Peer-reviewed
Ja
ÖFOS 2012
103015 Kondensierte Materie, 103025 Quantenmechanik
Schlagwörter
Link zum Portal
https://ucrisportal.univie.ac.at/de/publications/f9aa7dfe-71e7-4644-aa09-d17f9b943094