Measuring Entanglement During Chemical Dynamics

With support from the Chemical Structure and Dynamics (CSD) program in the Chemistry Section, Professor Stephen Leone at the University of California, Berkeley is establishing a comprehensive framework for characterizing and controlling quantum coherence and entanglement in atomic and molecular systems. This program aims to address entanglement as a time-resolved parameter in chemical dynamics. The challenges of identifying and experimentally characterizing entanglement dynamics require precision laser measurements that can project the necessary coherence and entanglement information onto optical detectors on very short timescales. To accomplish this, Professor Leone and his students will integrate coincidence detection of dual velocity map imaging spectrometers with a tabletop attosecond extreme ultraviolet system to probe and quantify the ultrafast dynamics of electron-ion entanglement following photoionization. The research will obtain entanglement dynamics on very short timescales and directly test the interplay between coherence and entanglement in chemical processes. These studies will advance the fundamental understanding of ultrafast quantum dynamics and lay the groundwork for future applications in quantum information processing and quantum sensing. Students trained on this project learn strategic technologies that impact the economy, related to precision timing and synchronization, nanopatterning and lithography at small dimensions, optical communications, and sensing using quantum information science principles. Previous studies of chemical kinetics and dynamics produced a wealth of information about product species, state-resolved dynamics, and coherence phenomena, establishing a broad basis for understanding mechanisms. Whenever two particles are formed from one particle in a chemical process, such as photoionization or dissociation, entanglement can occur between the outgoing particles. Here entanglement is measured by probing features such as quasi-bound autoionizing states embedded in a continuum during photoionization. This imparts nontrivial dynamics to the photoionization, resulting in modifications to the degree of entanglement versus time between the resulting photoelectron and ion due to quantum path interferences of the finite lifetime autoionizing states. The ultimate timescale for the formation of the final degree of entanglement will also be accessible as a function of chemical system. When one of the particles also has two or more formal quantum states, coherence can occur among these states. The tradeoff between entanglement and coherence is anti-correlated, providing a deep understanding of the evolution of the quantum dynamics that governs the chemical process. This is made possible by simultaneous tomographic and coincidence measurements of processes that take place in a continuum. 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.