Resonant energy transfer between Rydberg atoms and polar ground-state molecules at temperatures below 100 mK*

Resonant energy transfer, arising as a result of dipole-dipole interactions between helium Rydberg atoms and cold ground-state ammonia molecules, has been studied at temperatures below 100 mK in an intra beam collision apparatus [1,2]. In the experiments, the atoms were prepared in triplet ns Rydberg states, with principal quantum numbers between n = 38 and 40. The process of energy transfer to np states, and l-mixed Rydberg Stark states, was tuned through resonance using electric fields up to 8 V/cm. This allowed resonance widths as low as 100 MHz to be observed. These widths are attributed to binary atom-molecule collisions at mean center-of-mass collision speeds of 20 m/s (i.e., a center-of-mass collision energy corresponding to ~100 mK). The measured resonance widths are strongly Rydberg state dependent and are broadened by van der Waals interactions that are enhanced in the presence of larger electric fields. These effects have been interpreted by comparison of the experimental data with the results of numerical calculations of the Stark shifts and the static dipole-dipole interactions in the collisions. These types of low-temperature atom-molecule interaction are of interest for cold chemistry, non-destructive detection of cold molecules, and quantum simulation [3-6].

References

[1] K. Gawlas and S. D. Hogan, J. Phys. Chem. Lett. 11, 83 (2020)

[2] J. Zou and S. D. Hogan, Phys. Rev. A 106, 043111 (2022)

[3] F. Jarisch and M. Zeppenfeld, New J. Phys. 20, 113044 (2018)

[4] E. Kuznetsova, S. T. Rittenhouse, H. R. Sadeghpour, and S. F. Yelin, Phys. Chem. Chem. Phys. 13, 17115 (2011).

[5] K. Wang, C. P. Williams, L. R. B. Picard, N. Y. Yao and K.-K. Ni, PRX Quantum 3, 030339 (2022)

[6] C. Zhang and M.R. Tarbutt, PRX Quantum 3, 030340 (2022)