QLC: EAGER: Collaborative Research: New Design for Quantum Chemistry Calculations on Emerging Quantum Computers

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

James Freericks of Georgetown University and Dominika Zgid of Northwestern University are supported by an EAGER award from the Chemical Theory, Models and Computational program in the Division of Chemistry to develop approaches to solve quantum chemistry problems on quantum computers. Computers are often employed to make predictions of different scientific phenomena. In quantum chemistry, computations can be employed to determine the total energy of a molecule, how the molecule vibrates and rotates, how it interacts with light, and how it changes in a chemical reaction. Some quantum chemistry problems are too difficult to be solved with even the most powerful supercomputer. Fortunately, completely new types of computers, called quantum computers, are now being made as early prototype machines. These quantum computers are programmed within a paradigm that uses quantum mechanics for their operation. Hence, they are well suited to solve difficult quantum chemistry problems. Freericks, Zgid and their coworkers design strategies for how to solve a range of different quantum chemistry problems on these quantum computers. The project is designing algorithms from scratch which are then tested on quantum computers when appropriate machines are available. The broader impact of this work includes introducing undergraduates, high school students, and citizen scientists to the field of quantum chemistry on quantum computers. The project also supports some development of chemistry topics in a quantum book entitled Quantum Mechanics without Calculus. This project focuses on using a hybrid quantum-classical approach to solving quantum chemistry problems. The quantum computer is employed to determining the effect of strong quantum interactions, while the conventional computer is used to calculate how best to initialize the quantum computer and how to incorporate the results from the quantum computer into determining the final answers. The work employs Green's function methods to vastly improve the accuracy and efficiency of the calculations as the quality of the quantum hardware improves to allow moderate circuit depth. The end-product of this work may be an accurate demonstration of the viability of quantum computers to describe complex quantum chemical phenomena. The initial focus is on small chemical systems like the CrH dimer, which can be simulated on a 16-qubit machine, and then expanded to more complicated systems, such as (NiO)2 and (NiO)4, as hardware and algorithmic developments allow. Partnerships with industry run the lower circuit depth algorithms on superconducting-based quantum computers, such as those available at IBM, and on ion-trap-based quantum computers, such as those being developed at IonQ. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.