How quantum could help

Photodynamic therapy (PDT) is a promising cancer treatment that uses light-activated photosensitisers, but designing new drugs for this requires modeling complex excited-state processes, which is a known computationally intensive task and which classical computing falls short of. Quantum simulation could be used in a fully integrated quantum–classical pipeline for excited-state simulations and to identify key challenges in modelling clinically relevant compounds such as TLD-1433—a ruthenium-based PDT drug currently in clinical trials. Research has enabled quantum computers to be initialised in states with high overlap to desired reference states, a longstanding bottleneck in quantum chemistry, and an improvement which also extends well beyond PDT applications. Thus tackling these issues with quantum simulation would address a fundamental challenge within PDT.