Variational Quantum Algorithm for Quantum Dynamics

Abstract

Simulating quantum dynamics on classical computers remains challenging on classical computers due to the exponentially large Hilbert space. On the other hand, quantum computers are naturally suited for quantum simulations. This paper explores the state-of-the-art variational quantum algorithm for simulating quantum dynamics using near-term quantum devices. In essence, the most expensive part of the calculation is done on the quantum machine which can take advantage of the quantum speed up. The relatively straight forward optimization process is conducted on a classical computer. This hybrid approach makes best use of the two computing architectures to solve the challenging problems in quantum dynamic simulation. We apply the algorithm to the electron tunneling dynamics in chemical reactions. The workflow includes constructing a Hamiltonian that represents the energy levels of the system and the electronic coupling strength, designing quantum circuits, and running the algorithm on real quantum devices. The algorithm design and its application will demonstrate practical use cases of quantum computing in quantum simulation.