Finite Temperature Simulation of Non-Markovian Quantum Dynamics in Condensed Phase using Quantum Computers

George Mason University, Fairfax VA

Investigators

Abstract

With support from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry, Fei Wang of George Mason University will work to develop efficient quantum algorithms to perform condensed phase quantum dynamics simulations on quantum computers. Many important physical and chemical processes occur in the condensed phase, spanning chemical reactions in solutions, charge transfer at semiconductor interfaces, and solar energy conversion in molecular aggregates. The scientific investigation of these processes not only promotes our fundamental understanding but also offers practical solutions to materials design and environmental sustainability. As many of these processes involve charge migration and excitation energy transfer, quantum dynamics involving many degrees of freedom is essential for their description. However, such simulations are resource intensive on classical computers. On the other hand, quantum computers are naturally suited for quantum simulations. With algorithm development, Dr. Wang is aiming to show quantum speedup for quantum dynamics simulations in condensed phases, and demonstrate practical applications of quantum computing in the area of quantum simulation. Graduate students and postdoctoral researchers involved in this project will receive rigorous training in quantum information science and master state-of-the-art quantum simulation tools. Through internship programs offered to undergraduate and high school students, the PI will support underrepresented and economically disadvantaged groups. These efforts will not only encourage broad participation in STEM (science, technology, engineering and mathematics), but also help to educate a future quantum workforce for careers in academia and industry. The focus of this work will be to develop efficient quantum algorithms for finite-temperature non-Markovian time evolution, which offers a general framework for condensed phase quantum dynamics. New advances in this project will cover unitary operator construction, efficient quantum circuit compilation, model and real system simulations, and performance comparison between different types of quantum devices. Three mathematical methods will be explored (unitary dilation, singular value decomposition, and linear combinations of unitary operators) for non-unitary to unitary conversion, and their effectiveness will be assessed based on complexity theory. Two general approaches will be investigated for circuit compilation: one performs the exact mathematical decomposition, and the other uses the variational quantum circuit method. The optimal circuit structure will be identified based on gate counts and circuit depth. The algorithm will be tested on spin-boson models as well as on realistic systems, and the performance of trapped ions and superconducting devices will be compared. The success of the algorithm will offer quantum speedup in simulations of multi-state non-Markovian quantum dynamics at finite temperature. A user-friendly and open-source platform will be put forward such that, with input parameters, dynamical simulations on a quantum computer can be carried out and the results analyzed. This work could potentially inspire future quantum algorithm design for simulating the dynamics of open quantum systems. 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.