Quantum simulation of molecules in solution

Abstract

Quantum chemical calculations on quantum computers have been focused mostly on simulating molecules in gas-phase. Molecules in liquid solution are however most relevant for Chemistry. Continuum solvation models represent a good compromise between computational affordability and accuracy in describing solvation effects within a quantum chemical description of solute molecules. Here we report on the extension of the Variational Quantum Eigensolver to solvated systems, using the Polarizable Continuum Model. We show that accounting for solvation effects does not impact the algorithmic efficiency. Numerical results of noiseless simulations for molecular systems with up to twelve spin-orbitals (qubits) are presented. Furthermore, calculations performed on a simulated quantum hardware (IBM Q Mumbai), thus including noise, yield computed solvation free energies in fair agreement with the classical calculations without the inclusion of any error mitigation protocol.

Quantum chemistry simulation of ground- and excited-state properties of the sulfonium cation on a superconducting quantum processor

“…Solvation effects can be accounted for using implicit or explicit solvation models. 72,73 Research into these algorithmic extensions and improvements is underway.…”

Quantum chemistry simulation of ground- and excited-state properties of the sulfonium cation on a superconducting quantum processor

“…A number of challenges need to be addressed to provide chemically meaningful results, particularly in connection with the photo-acid generating properties of Ph 3 S + , by integrating additional functionalities in the algorithmic workflow considered here. These include: accounting for static and dynamical electron correlation in realistic basis sets, which can be achieved by perturbative or otherwise approximate techniques [60,61]; describing realistic ligands such as phenyl rings, for example by fragmentation techniques [62,63]; and accounting for solvent effects using implicit or explicit solvation models [64,65]. Encouragingly, the algorithmic workflow considered in this work appears useful, in conjunction with near-term quantum architectures and in combination with other algorithms, and serves to demonstrate the usefulness of hybrid quantum-classical simulation techniques in the continuing search for physically relevant simulations.…”