Quantum Simulation of Molecules in Solution

Abstract

Quantum chemical calculations on quantum computers have been focused mostly on simulating molecules in the 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. In this work, we extend the variational quantum eigensolver to simulate solvated systems using the polarizable continuum model. To account for the state dependent solute–solvent interaction we generalize the variational quantum eigensolver algorithm to treat non-linear molecular Hamiltonians. We show that including solvation effects does not impact the algorithmic efficiency. Numerical results of noiseless simulations for molecular systems with up to 12 spin-orbitals (qubits) are presented. Furthermore, calculations performed on a simulated noisy quantum hardware (IBM Q, Mumbai) yield computed solvation free energies in fair agreement with the classical calculations.

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.…”

A Vision for the Future of Multiscale Modeling

“…In the past few years, there have been considerable efforts to incorporate these approaches into the framework of multiscale modeling. Particularly, considering QM-continuum strategies, in ref the VQE has been coupled with IEF-PCM to compute molecular properties in solution. Along the same line, an implicit description of the solvation effects via the Reference-Interaction Site Model has been integrated with the VQE .…”

Solvent Distribution Effects on Quantum Chemical Calculations with Quantum Computers

“…Castaldo et al unified the VQE and an implicit solvent model, i.e., the polarizable continuum model (PCM) . 6 The PCM has also been used by Blunt et al to estimate the computational costs of the QPE for a protein− ligand binding system. 7 Izsak et al introduced a simple multilayer approach (the ONIOM approach, also known as subtractive QM/MM) for the VQE and QPE.…”

“…Thus far, studies have considered solvent effects within the framework of quantum computing. Castaldo et al unified the VQE and an implicit solvent model, i.e., the polarizable continuum model (PCM) . The PCM has also been used by Blunt et al to estimate the computational costs of the QPE for a protein–ligand binding system .…”