Projected Hartree-Fock as a Polynomial of Particle-Hole Excitations and Its Combination With Variational Coupled Cluster Theory

Abstract

Projected Hartree-Fock theory provides an accurate description of many kinds of strong correlation but does not properly describe weakly correlated systems. Coupled cluster theory, in contrast, does the opposite. It therefore seems natural to combine the two so as to describe both strong and weak correlations with high accuracy in a relatively black-box manner. Combining the two approaches, however, is made more difficult by the fact that the two techniques are formulated very differently. In earlier work, we showed how to write spin-projected Hartree-Fock in a coupled-cluster-like language. Here, we fill in the gaps in that earlier work. Further, we combine projected Hartree-Fock and coupled cluster theory in a variational formulation and show how the combination performs for the description of the Hubbard Hamiltonian and for several small molecular systems.

Published version

References in corpus (4)

• Merging symmetry projection methods with coupled cluster theory: Lessons from the Lipkin model Hamiltonian
• Extended Møller-Plesset perturbation theory for dynamical and static correlations
• Projected Hartree Fock Theory as a Polynomial Similarity Transformation Theory of Single Excitations
• Combining symmetry collective states with coupled cluster theory: Lessons from the Agassi model Hamiltonian

Cited by in corpus (15)

• Projected Coupled Cluster Theory
• Tensor-Structured Coupled Cluster Theory
• Particle-number projected Bogoliubov coupled cluster theory. Application to the pairing Hamiltonian
• Variational coupled cluster for ground and excited states
• Spin-projection for quantum computation: A low-depth approach to strong correlation
• Cluster decomposition of full configuration interaction wave functions: a tool for chemical interpretation of systems with strong correlation
• Projected Coupled Cluster Theory: Optimization of cluster amplitudes in the presence of symmetry projection
• Spin-Projected Generalized Hartree-Fock as a Polynomial of Particle-Hole Excitations
• Minimal matrix product states and generalizations of mean-field and geminal wavefunctions
• Combining symmetry collective states with coupled cluster theory: Lessons from the Agassi model Hamiltonian
• Symmetry-projected cluster mean-field theory applied to spin systems
• Symmetry projection to coupled-cluster singles and doubles wave function through the Monte Carlo method
• Approaching the Full Configuration Interaction Ground State from an Arbitrary Wavefunction with Gradient Descent and Quasi-Newton Algorithms
• Addressing Strong Correlation by Approximate Coupled-Pair Methods with Active-Space and Full Treatments of Three-Body Clusters
• Symmetry breaking and restoration on a fermionic quantum ring