Hybridization expansion Monte Carlo simulation of multi-orbital quantum impurity problems: matrix product formalism and improved sampling
- Shinaoka, Hiroshi Theoretische Physik, ETH Zürich, Switzerland
- Dolfi, Michele Theoretische Physik, ETH Zürich, Switzerland
- Troyer, Matthias Theoretische Physik, ETH Zürich, Switzerland
- Werner, Philipp Department of Physics, University of Fribourg, Switzerland
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01.06.2014
Published in:
- Journal of Statistical Mechanics: Theory and Experiment. - 2014, vol. 2014, no. 6, p. P06012
English
We explore two complementary modifications of the hybridization-expansion continuous-time Monte Carlo method, aiming at large multi-orbital quantum impurity problems. One idea is to compute the imaginary-time propagation using a matrix product state representation. We show that bond dimensions considerably smaller than the dimension of the Hilbert space are sufficient to obtain accurate results and that this approach scales polynomially, rather than exponentially with the number of orbitals. Based on scaling analyses, we conclude that a matrix product state implementation will outperform the exact-diagonalization based method for quantum impurity problems with more than 12 orbitals. The second idea is an improved Monte Carlo sampling scheme which is applicable to all variants of the hybridization expansion method. We show that this so-called sliding window sampling scheme speeds up the simulation by at least an order of magnitude for a broad range of model parameters, with the largest improvements at low temperature.
- Faculty
- Faculté des sciences et de médecine
- Department
- Département de Physique
- Language
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- English
- Classification
- Physics
- License
- License undefined
- Identifiers
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- RERO DOC 231840
- DOI 10.1088/1742-5468/2014/06/P06012
- Persistent URL
- https://folia.unifr.ch/unifr/documents/303769
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