Dynamical cluster approximation: Nonlocal dynamics of correlated electron systems
- Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221 (United States)
We recently introduced the dynamical cluster approximation (DCA), a technique that includes short-ranged dynamical correlations in addition to the local dynamics of the dynamical mean-field approximation while preserving causality. The technique is based on an iterative self-consistency scheme on a finite-size periodic cluster. The dynamical mean-field approximation (exact result) is obtained by taking the cluster to a single site (the thermodynamic limit). Here, we provide details of our method, explicitly show that it is causal, systematic, {phi} derivable, and that it becomes conserving as the cluster size increases. We demonstrate the DCA by applying it to a quantum Monte Carlo and exact enumeration study of the two-dimensional Falicov-Kimball model. The resulting spectral functions preserve causality, and the spectra and the charge-density-wave transition temperature converge quickly and systematically to the thermodynamic limit as the cluster size increases. (c) 2000 The American Physical Society.
- OSTI ID:
- 20216423
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 61, Issue 19; Other Information: PBD: 15 May 2000; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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