Comparison of two quantum-cluster approximations
强关联电子
2009-11-07 v2 统计力学
摘要
We provide microscopic diagrammatic derivations of the the Molecular Coherent Potential Approximation (MCA) and Dynamical Cluster Approximation (DCA) and show that both are Phi-derivable. The MCA (DCA) maps the lattice onto a self-consistently embedded cluster with open (periodic) boundary conditions, and therefore violates (preserves) the translational symmetry of the original lattice. As a consequence of the boundary conditions, the MCA (DCA) converges slowly (quickly) with corrections O(1/Lc) (O(1/Lc^2)), where Lc is the linear size of the cluster. These analytical results are demonstrated numerically for the one-dimensional symmetric Falicov-Kimball model.
引用
@article{arxiv.cond-mat/0110192,
title = {Comparison of two quantum-cluster approximations},
author = {Th. A. Maier and M. Jarrell},
journal= {arXiv preprint arXiv:cond-mat/0110192},
year = {2009}
}
备注
corrected version