The Jastrow antisymmetric geminal power in Hilbert space: theory, benchmarking, and application to a novel transition state

TL;DR

The paper introduces the Jastrow antisymmetric geminal power (JAGP) ansatz in Hilbert space, demonstrating its efficiency and accuracy in describing complex electronic correlations and transition states, outperforming many existing methods.

Contribution

It presents efficient quantum Monte Carlo algorithms for JAGP, showcasing its ability to handle static and dynamic correlations in challenging molecular systems.

Findings

JAGP accurately describes bond stretching in H2O, C2, N2

JAGP effectively models a novel transition state of ethene

JAGP outperforms single-reference methods in accuracy

Abstract

The Jastrow-modified antisymmetric geminal power (JAGP) ansatz in Hilbert space successfully overcomes two key failings of other pairing theories, namely a lack of inter-pair correlations and a lack of multiple resonance structures, while maintaining a polynomially scaling cost, variational energies, and size consistency. Here we present efficient quantum Monte Carlo algorithms that evaluate and optimize the JAGP energy for a cost that scales as the fifth power of the system size. We demonstrate the JAGP's ability to describe both static and dynamic correlation by applying it to bond stretching in H2O, C2, and N2 as well as to a novel, multi-reference transition state of ethene. JAGP's accuracy in these systems outperforms even the most sophisticated single-reference methods and approaches that of exponentially-scaling active space methods.