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Building a Single Molecule from a Reservoir of Two atoms


For over two decades, ultracold neutral atoms have served as workhorses in experimental quantum science. Their indistinguishability, available internal states featuring long coherence times or large dipole moments, low configuration entropy, and ability to be manipulated with electromagnetic fields make them ideally suited for applications ranging across quantum many-body physics and quantum simulation, quantum networks, quantum information processing, precision measurements, and the study of cold collisions. Spurred by these successes, there has been a flurry of activity to bring neutral molecules under the same level of control. Here, we propose a bottom-up solution to gain single particle control of ultracold molecules for the first time.

We use optical tweezers to deterministically assemble a single NaCs molecule in a single quantum state from a pair of Na and Cs atoms [1]. In the process, we realize a conceptually simple platform for studying atomic collisions and molecular spectra which derives its strength from the ability to gather ``before" and ``after" images of single atoms [2].

1. Liu, L. R., Hood, J. D., Yu, Y., Zhang, J. T., Wang, K., Lin, Y.-W., Rosenband, T., & Ni, K. PRX 9, 2 (2019).

2. Liu, L. R., Hood, J. D., Yu, Y., Zhang, J. T., Hutzler, N. R., Rosenband, T., & Ni, K. K. Science 360, 6391 (2018).