Comparison of two quantum-cluster approximations
Th. A. Maier, M. Jarrell
Abstract
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/Lc2)), where Lc is the linear size of the cluster. These analytical results are demonstrated numerically for the one-dimensional symmetric Falicov-Kimball model.
Create a lesson
Related papers
Hidden entropic order of emergent charges in a classical Ampère spin liquid
H. Diego Rosales, Emma M. Bizot, Flavia A. Gómez Albarracín et al.
Stability of energy gap of macroscopic quantum matter
Kangle Li, Liujun Zou
Field evolution of the multi-k magnetic states in NdB4 revealed by neutron diffraction
D. Brunt, N. Qureshi, E. Chan et al.
Interplay between Spin Stripes and Pairing Crossover in the Bilayer Hubbard Model
Zixuan Jia, Xuelei Sui, Shijie Hu et al.
Ni ordering in the van der Waals gap of Ni-intercalated 2H-NbS2: from disorder through 2×2 and 3×3 order to stripe order
Naveen Singh Dhami, Ricardo Guillermo Torres Ramirez, Gaurav Pransu et al.
Resonantly interacting 2e/3 anyons: a controlled microscopic theory of anyon superconductivity
Qingchen Li, Pavel A. Nosov, Zhaoyu Han et al.