# Quantum Monte Carlo tunneling from quantum chemistry to quantum annealing

## TL;DR

This paper demonstrates that quantum Monte Carlo simulations can efficiently recover tunneling rates in high-dimensional models, with implications for quantum chemistry and quantum annealing.

## Contribution

It extends previous results to continuous variable models, showing QMC's effectiveness in capturing tunneling phenomena in complex systems.

## Key findings

- QMC simulations recover ground state tunneling rates via instanton paths.
- QMC results have implications for quantum chemical reactions.
- Quantum tunneling can be a resource in quantum annealing.

## Abstract

Quantum Tunneling is ubiquitous across different fields, from quantum chemical reactions, and magnetic materials to quantum simulators and quantum computers. While simulating the real-time quantum dynamics of tunneling is infeasible for high-dimensional systems, quantum tunneling also shows up in quantum Monte Carlo (QMC) simulations that scale polynomially with system size. Here we extend a recent results obtained for quantum spin models {[{Phys. Rev. Lett.} {\bf 117}, 180402 (2016)]}, and study high-dimensional continuos variable models for proton transfer reactions. We demonstrate that QMC simulations efficiently recover ground state tunneling rates due to the existence of an instanton path, which always connects the reactant state with the product. We discuss the implications of our results in the context of quantum chemical reactions and quantum annealing, where quantum tunneling is expected to be a valuable resource for solving combinatorial optimization problems.