Research Projects

Quantum chemical simulations are crucial for predicting kinetics and thermodynamics of chemical reactions, tuning thermal, electrochemical, and photochemical reactivity, and designing novel molecules and materials for medical and technological applications. However, accuracy is often limited by computing time and memory requirements, which scale exponentially with the number of electrons. Quantum computing, first envisioned by Richard Feynman in the 1980s, aims to be exponentially more powerful than classical computers due to quantum level properties like superposition and entanglement. However, capturing this power is challenging due to the delicate nature of quantum objects, which lose their superposition upon interaction with external noise. To address this issue, researchers are developing error correction codes and algorithms. Hybrid quantum-classical algorithms, such as the variational quantum eigensolver (VQE) algorithm, have been developed to make the best use of both classical and quantum processors. VQE has been successfully applied to calculate ground-state energies of several small molecules, spurring research interest in extending the algorithm to model electronic excited states. The present project aims to evaluate the performance of recently developed VQE-based excited-state algorithms in simulating photophysics and photochemistry of small molecules on NIsQ devices. The project also aims to integrate valence bond theory (VBT) with the VQE algorithm to develop a fast and accurate method for simulating excited states in photophysical processes and photochemical reactions on quantum computers.