Orbital entanglement and correlation from pCCD-tailored Coupled Cluster wave functions

Abstract

Wave functions based on electron-pair states provide inexpensive and reliable models to describe quantum many-body problems containing strongly-correlated electrons, given that broken-pair states have been appropriately accounted for by, for instance, a posteriori corrections. In this article, we analyse the performance of electron-pair methods in predicting orbital-based correlation spectra. We focus on the (orbital-optimized) pair-coupled cluster Doubles (pCCD) ansatz with a linearized coupled-cluster (LCC) correction. Specifically, we scrutinize how orbital-based entanglement and correlation measures can be determined from a pCCD-tailored CC wave function. Furthermore, we employ the single-orbital entropy, the orbital-pair mutual information, and the eigenvalue spectra of the two-orbital reduced density matrices to benchmark the performance of the LCC correction for the one-dimensional Hubbard model with periodic boundary condition as well as the N${}_2$ and F${}_2$ molecules against DMRG reference calculations. Our study indicates that pCCD-LCC accurately reproduces the orbital-pair correlation patterns in the weak-correlation limit and for molecules close to their equilibrium structure. Hence, we can conclude that pCCD-LCC predicts reliable wave functions in this regime. In the strong-correlation limit and for molecules with stretched bonds, the LCC correction, generally, overestimates orbital-pair correlations.

arXiv comment4 figures

References in corpus (34)

• Ab Initio Quantum Chemistry using the Density Matrix Renormalization Group
• Automated Selection of Active Orbital Spaces
• The Density Matrix Renormalization Group in Chemistry and Molecular Physics: Recent Developments and New Challenges
• Tensor product methods and entanglement optimization for ab initio quantum chemistry
• Measuring orbital interaction using quantum information theory
• Quantum information analysis of electronic states at different molecular structures
• Multireference Correlation in Long Molecules with the Quadratic Scaling Density Matrix Renormalization Group
• Entanglement Measures for Single- and Multi-Reference Correlation Effects
• Quantum data compression, quantum information generation, and the density-matrix renormalization group method
• Seniority-based coupled cluster theory
• Two-site entropy and quantum phase transitions in low-dimensional models
• Efficient description of strongly correlated electrons with mean-field cost
• Orbital entanglement in bond-formation processes
• Orbital entanglement in quantum chemistry
• Projected seniority-two orbital optimization of the Antisymmetric Product of one-reference orbital Geminal
• autoCAS: a program for fully automated multi-configurational calculations
• Linearized Coupled Cluster Correction on the Antisymmetric Product of 1 reference orbital Geminals
• Second-Order Self-Consistent-Field Density-Matrix Renormalization Group
• Concept of orbital entanglement and correlation in quantum chemistry
• T3NS: three-legged tree tensor network states
• The correlation theory of the chemical bond
• Analysis of two-orbital correlations in wavefunctions restricted to electron-pair states
• Targeting doubly-excited states with Equation of Motion Coupled Cluster theory restricted to double excitations
• Quantum Entanglement in Carbon-Carbon, Carbon-Phosphorus and Silicon-Silicon Bonds
• Unravelling the quantum-entanglement effect of noble gas coordination on the spin ground state of CUO
• Correlation paradox of the dissociation limit: A quantum information perspective
• A quantum informational approach for dissecting chemical reactions
• Benchmarking the accuracy of seniority-zero wavefunction methods for non-covalent interactions
• Modeling the electronic structures of the ground and excited states of the ytterbium atom and the ytterbium dimer: A modern quantum chemistry perspective
• On the Multi-Reference Nature of Plutonium Oxides: PuO${}_2^{2+}$, PuO${}_2$, PuO${}_3$ and PuO${}_2$(OH)${}_2$
• Assessing the accuracy of simplified Coupled Cluster methods for electronic excited states in f0 actinide compounds
• Actinide chemistry using singlet-paired coupled cluster and its combinations with density functionals
• Number-parity effect for confined fermions in one dimension
• Dissecting the Bond Formation Process of $d^{10}$-Metal-Ethene Complexes with Multireference Approaches

Cited by in corpus (16)

• Pythonic Black-box Electronic Structure Tool (PyBEST). An open-source Python platform for electronic structure calculations at the interface between chemistry and physics
• Density Matrices of Seniority-Zero Geminal Wavefunctions
• A configuration interaction correction on top of pair coupled cluster doubles
• The relationship between structure and excited-state properties in polyanilines from geminal-based methods
• Reduced density matrix functional theory from an ab initio seniority-zero wave function: Exact and approximate formulations along adiabatic connection paths
• Static Embedding with Pair Coupled Cluster Doubles Based Methods
• Coupled cluster method tailored with quantum computing
• Delving into the Catalytic Mechanism of Molybdenum Cofactors: A Novel Coupled Cluster Study
• Benchmarking ionization potentials from the simple pCCD model
• Orbital Entanglement and The Double $d$-Shell Effect in Binary Transition Metal Molecules
• Time-Reversal Symmetry in RDMFT and pCCD with Complex-Valued Orbitals
• Seniority-zero Linear Canonical Transformation Theory
• Spin-free orbital entropy, mutual information, and correlation analysis
• DMRG-tailored coupled cluster method in the 4c-relativistic domain: General implementation and application to the NUHFI and NUF${}_3$ molecules
• Quantum information theory on sparse wavefunctions and applications for Quantum Chemistry
• Transition density matrices of Richardson-Gaudin states