Abstract
We provide microscopic diagrammatic derivations of the molecular coherent potential approximation (MCA) and dynamical cluster approximation (DCA) and show that both are Φ 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/Lc2)], where Lc is the linear size of the cluster. These analytical results are demonstrated numerically for the onedimensional symmetric Falicov-Kimball model.
Original language | English |
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Article number | 041104 |
Pages (from-to) | 411041-411044 |
Number of pages | 4 |
Journal | Physical Review B - Condensed Matter and Materials Physics |
Volume | 65 |
Issue number | 4 |
State | Published - Jan 15 2002 |
Externally published | Yes |