Quantum chemistry based on classical mechanics inspired by simulated bifurcation

TL;DR

This paper introduces SBCI, a classical mechanics-inspired algorithm for quantum chemistry calculations, which reduces computational costs while maintaining high accuracy, potentially accelerating electronic structure computations.

Contribution

It presents a novel SBCI algorithm derived from simulated bifurcation, offering a more efficient alternative for FCI calculations in quantum chemistry.

Findings

SBCI reduces computation time compared to standard methods.

SBCI maintains high accuracy in molecular property calculations.

SBCI demonstrates potential for large-scale electronic structure calculations.

Abstract

Accurate quantum chemical calculations are critical for understanding molecular properties, yet their computational cost remains a major challenge. Full Configuration Interaction (FCI) provides exact solutions but is prohibitively expensive for large systems. To address this, quantum computers are expected to be useful, but developing practical quantum computers is still ongoing. Here we introduce an efficient Configuration Interaction (CI) computation algorithm based on classical mechanics, which we call Simulated Bifurcation-based CI (SBCI), because we derive this algorithm from a quantum inspired algorithm for combinatorial optimization called Simulated Bifurcation. Applying it to FCI computations of representative molecular systems and comparing the results with those by a standard method, we demonstrate that SBCI can reduce computation costs such as computation times and/or required memory sizes, while keeping high accuracy comparable to the standard method. Thus, SBCI will be promising for accelerating high-precision electronic structure calculations without compromising reliability.