A novel FLEX supplemented QMC approach to the Hubbard model

Abstract

This paper introduces a novel ansatz-based technique for solution of the Hubbard model over two length scales. Short range correlations are treated exactly using a dynamical cluster approximation QMC simulation, while longer-length-scale physics requiring larger cluster sizes is incorporated through the introduction of the fluctuation exchange (FLEX) approximation. The properties of the resulting hybrid scheme are examined, and the description of local moment formation is compared to exact results in 1D. The effects of electron-electron coupling and electron doping on the shape of the Fermi-surface are demonstrated in 2D. Causality is examined in both 1D and 2D. We find that the scheme is successful if QMC clusters of $N_C\ge 4$ are used (with sufficiently high temperatures in 1D), however very small QMC clusters of $N_C=1$ lead to acausal results.

References in corpus (5)

• Nonlocal Dynamical Correlations of Strongly Interacting Electron Systems
• Extended Dynamical Mean Field Theory and GW method
• A Quantum Monte Carlo algorithm for non-local corrections to the Dynamical Mean-Field Approximation
• Phase Diagram of the Hubbard Model: Beyond the Dynamical Mean Field
• Analysis of the dynamical cluster approximation for the Hubbard model

Cited by in corpus (9)

• Quantum Cluster Theories
• Diagrammatic routes to nonlocal correlations beyond dynamical mean field theory
• From infinite to two dimensions through the functional renormalization group
• Dynamical vertex approximation in its parquet implementation: application to Hubbard nano-rings
• Multi-scale Extensions to Quantum Cluster Methods for Strongly Correlated Electron Systems
• Correlated starting points for the functional renormalization group
• Real-space cluster dynamical mean-field theory: Center focused extrapolation on the one- and two particle level
• Interplay of Pomeranchuk instability and superconductivity in the two-dimensional repulsive Hubbard model
• Strongly correlated superconductivity with long-range spatial fluctuations