Seniority-zero Linear Canonical Transformation Theory
arXiv:2509.19085 · doi:10.1063/5.0309818
Abstract
We propose a method to solve the electronic Schrödinger equation for strongly correlated systems by applying a unitary transformation to reduce the complexity of the physical Hamiltonian. In particular, we seek a transformation that maps the Hamiltonian into the seniority-zero space: seniority-zero wavefunctions are computationally simpler, but still capture strong correlation within electron pairs. The unitary rotation is evaluated using the Baker Campbell Hausdorff (BCH) expansion, truncated to two-body operators through the operator decomposition strategy of canonical transformation (CT) theory, which rewrites higher-rank terms approximately in terms of one- and two-body operators. Unlike conventional approaches to CT theory, the generator is chosen to minimize the size of non-seniority-zero elements of the transformed Hamiltonian. Numerical tests reveal that this Seniority-zero Linear Canonical Transformation (SZ-LCT) method delivers highly accurate results, usually with submilliHartree error. The effective computational scaling of SZ-LCT is , where is the number of cores available for the computation.
11 pages, 6 figures
References in corpus (22)
- Recent developments in the PySCF program package
- Generalized Unitary Coupled Cluster Wavefunctions for Quantum Computation
- Seniority-based coupled cluster theory
- Can single-reference coupled cluster theory describe static correlation?
- Efficient description of strongly correlated electrons with mean-field cost
- A numerical canonical transformation approach to quantum many body problems
- A driven similarity renormalization group approach to quantum many-body problems
- Projected seniority-two orbital optimization of the Antisymmetric Product of one-reference orbital Geminal
- Linearized Coupled Cluster Correction on the Antisymmetric Product of 1 reference orbital Geminals
- Orbital-optimized pair-correlated electron simulations on trapped-ion quantum computers
- Excited States From State Specific Orbital Optimized Pair Coupled Cluster
- Towards numerically robust multireference theories: The driven similarity renormalization group truncated to one- and two-body operators
- Simulating quantum chemistry in the seniority-zero space on qubit-based quantum computers
- Correlating the Antisymmetrized Geminal Power Wave Function
- Orbital entanglement and correlation from pCCD-tailored Coupled Cluster wave functions
- Spin-free formulation of the multireference driven similarity renormalization group: A benchmark study of first-row diatomic molecules and spin-crossover energetics
- Reduced Density Matrices / Static Correlation Functions of Richardson-Gaudin States Without Rapidities
- A configuration interaction correction on top of pair coupled cluster doubles
- Structure of the number projected BCS wave function
- Active Space Pair 2-Electron Reduced Density Matrix Theory for Strong Correlation
- A Hybrid Qubit Encoding: Splitting Fock Space into Fermionic and Bosonic Subspaces
- Jordan-Wigner Transformation for the Description of Strong Correlation in Fermionic Systems