Self-Consistent Effective Hamiltonian Theory for Fermionic Many Body Systems

TL;DR

This paper introduces a self-consistent effective Hamiltonian approach for fermionic many-body systems, demonstrating its effectiveness on the 2D Hubbard model and revealing a novel quadruple-fermion order parameter.

Contribution

It develops a new variational wavefunction-based method for fermionic systems and uncovers a previously unknown quadruple-fermion order in the 2D Hubbard model.

Findings

Effective Hamiltonian theory applied to 2D Hubbard model

Discovery of a quadruple-fermion non-Cooper-pair order parameter

Demonstrated computational efficiency of the approach

Abstract

Using a separable many-body variational wavefunction, we formulate a self-consistent effective Hamiltonian theory for fermionic many-body system. The theory is applied to the two-dimensional Hubbard model as an example to demonstrate its capability and computational effectiveness. Most remarkably for the Hubbard model in 2-d, a highly unconventional quadruple-fermion non-Cooper-pair order parameter is discovered.