Two Quantum Cluster Approximations
Th. A. Maier, O. Gonzalez, M. Jarrell, Th. Schulthess
Abstract
We provide microscopic diagrammatic derivations of 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/Lc2)), where Lc is the linear size of the cluster. However, local quantities, when measured in the center of the MCA cluster, converge more quickly than the DCA result. These results are demonstrated numerically for the one-dimensional symmetric Falicov-Kimball model.
Create a lesson
Related papers
A new approach to the Kondo effect: sophomore's dream function and Lee-Yang zeros
V. Yu. Irkhin
Temperature evolution of spin dynamics in extended Kitaev models within an Abrikosov fermion theory beyond mean field
Daiki Sasamoto, Joji Nasu
Interplay of disorder and spin liquid physics in the triangular-lattice antiferromagnet YbZn2GaO5
Hafsa Zeroual, Shams Sohel Islam, Toni Shiroka et al.
X-ray absorption spectroscopic studies of oxygen-deficient double perovskite oxide NdBaCo2O5+δ (δ 0.65)
Himanshu Pant, S. Khalid, R. Bindu
Odd-Parity Crystalline Electric Field and Multipoles in Icosahedral Quasicrystal and Approximant: Magnetic Toroidal and Electric Dipoles in Ce-Based Systems
Shinji Watanabe, Syunta Furuya, Mitsuaki Kawamura
Real-Time Relaxation Dynamics of Dark Excitons in Mirror-Symmetric Monolayers
Rishabh Saraswat, Mantasha Ansari, Rekha Verma et al.