MPS/CHE-EPSRC: Quantifying Utilizable Entanglement in Chemistry from First Principles

Researchers from Emory University along with their collaborators at University College London in the United Kingdom are developing new ways to understand and use quantum entanglement in molecules. Molecules are governed by quantum mechanics, but it is often unclear which fundamentally quantum phenomena are strong enough, long-lived enough, and controllable enough to affect chemical properties. This project is establishing the fundamental principles needed to design molecules as chemically tunable quantum systems for sensing, information processing, and other quantum technologies, while enabling new strategies for controlling chemical behavior through quantum phenomena. The research will focus on entanglement, a form of quantum correlation that cannot be explained by classical probability alone. The research team will use theoretical models and first-principles quantum chemistry methods to identify when entanglement in molecules can be detected, sustained, and connected to measurable properties. Their discoveries could establish design principles for molecules in which quantum correlations influence reactivity, selectivity, and spectroscopy. The project will also create web-based educational materials and open-source software to help students and researchers connect quantum information concepts with chemistry. This award is made under the NSF-UKRI lead agency opportunity. The project will introduce the concept of utilizable entanglement in chemistry, defined as quantum correlations that are chemically accessible, robust under realistic conditions, amenable to control, and connected to observable properties. The researchers will pursue three linked goals. First, they will develop multicomponent theoretical models for entanglement among electrons, protons, photons, phonons, excitons, and related molecular degrees of freedom, including fermion-fermion and fermion-boson Hamiltonians. These models will be used to determine how multipartite entanglement emerges and how it changes with temperature, environmental coupling, and molecular parameters. Second, the team will develop methods to identify chemical signatures of quantum correlation, including automated subsystem partitioning, entanglement witnesses based on experimentally accessible observables, and measures of entanglement strength. Third, the researchers will create computational approaches for molecular design by extending quantum chemistry methods to compute entanglement metrics and by applying them to extended polyaromatic hydrocarbons. These studies will connect polyradical character, spin entanglement, and the singlet-triplet gap, providing a test case for using quantum information measures to guide molecular design. 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.