Symmetric Tensor Decomposition Description of Fermionic Many-Body Wavefunctions

TL;DR

This paper introduces a symmetric tensor decomposition approach to reformulate the configuration interaction series for fermionic systems, making it more compact and computationally feasible while retaining accuracy.

Contribution

The authors develop a symmetric tensor decomposition method that converts the CI series into a compact form, improving the practicality of full-CI calculations for many-body fermionic wavefunctions.

Findings

The STD-CI series converges rapidly to the full-CI state.

The method is numerically tested on small molecules, showing promising results.

The series length grows moderately with system complexity.

Abstract

The configuration interaction (CI) is a versatile wavefunction theory for interacting fermions but it involves an extremely long CI series. Using a symmetric tensor decomposition (STD) method, we convert the CI series into a compact and numerically tractable form. The converted series encompasses the Hartree-Fock state in the first term and rapidly converges to the full-CI state, as numerically tested using small molecules. Provided that the length of the STD-CI series grows only moderately with the increasing complexity of the system, the new method will serve as one of the alternative variational methods to achieve full-CI with enhanced practicability.