MPS/CHE-EPSRC: Coherence Control of Ultracold Molecules and Matter-wave Interferometry of Chemical Processes

Researchers from the University of Chicago along with their collaborators at Durham University in the United Kingdom are developing new approaches to preserve and control quantum coherence in ultracold molecules for applications in quantum information science and quantum-controlled chemistry. Molecules offer exciting opportunities for future quantum technologies because they possess electronic, vibrational, rotational, and nuclear-spin degrees of freedom that together form a much richer quantum system than atoms alone. However, these same internal degrees of freedom also make molecular quantum states highly susceptible to environmental noise, presenting a major obstacle to using molecules as reliable quantum memories and processors. The research team will combine precision spectroscopy, ultracold molecular Bose-Einstein condensates, and advanced theoretical modeling to identify symmetry-protected molecular states that naturally resist decoherence while enabling coherent manipulation of quantum information. Their discoveries could establish new principles for protecting quantum information in molecular systems, advance the understanding of coherent chemical dynamics, and broaden the role of molecules as a scalable platform for Quantum Information Science. The project will provide interdisciplinary research opportunities for graduate and undergraduate students, expand outreach programs that engage local high-school students in quantum science, and strengthen international research partnerships through student exchanges and collaborative training between the United States and the United Kingdom. This award is made under the NSF-UKRI lead agency opportunity. The project will investigate how spin-exchange symmetries in ultracold bi-alkali molecules give rise to decoherence-free subspaces that protect quantum information encoded in nuclear-spin states. The theoretical effort at Durham University will develop coupled-channel scattering calculations and symmetry analyses to identify protected molecular subspaces, characterize emergent SU(8)-like symmetry, and quantify symmetry-breaking interactions arising from spin-orbit and hyperfine couplings. The experimental effort at the University of Chicago will employ high-resolution microwave spectroscopy of ultracold Cs₂ molecular Bose-Einstein condensates to observe these protected states, measure their coherence properties, and test theoretical predictions. The project will also develop molecular matter-wave interferometry to probe coherent chemical reactions and investigate quantum many-body effects in atom-molecule conversion dynamics. By integrating precision experiment with quantitative theory, the research will establish a framework for symmetry-protected quantum control in ultracold molecules and advance molecular platforms for quantum information processing, coherent chemistry, and precision quantum measurement. 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.