A fast path integral method for polarizable force fields.

Area of Science:

• Computational Chemistry
• Quantum Simulation
• Statistical Mechanics

Background:

• Quantum simulations of imaginary time path integrals are computationally demanding, scaling with the number of ring polymer beads (n).
• Classical simulations offer a computational advantage, but accurately capturing quantum effects requires specialized techniques.

Purpose of the Study:

• To develop and test a novel quantum simulation method that reduces computational cost for systems with polarizable force fields.
• To achieve computational efficiency approaching classical methods for complex molecular systems.

Main Methods:

• Decomposing the potential into slowly and rapidly varying contributions.
• Utilizing a contracted ring polymer approach with fewer beads for slowly varying parts.
• Iterating induction on the contracted ring polymer and applying transformations to obtain forces.
• Splitting the Coulomb potential into short- and long-range components.

Main Results:

• The developed method significantly reduces computational effort for quantum simulations of path integrals.
• The approach achieves near-classical computational cost in the limit of large system sizes.
• Successful application to simulations of liquid water and hexagonal ice using a polarizable Thole-type potential.

Conclusions:

• The proposed method offers a computationally efficient alternative for quantum simulations of systems with polarizable force fields.
• This technique is particularly advantageous for large molecular systems, bridging the gap between quantum and classical simulation costs.
• The study demonstrates the practical applicability of the method in condensed-phase systems.