Beecroft Building, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU
Dr Philip Gregory, Durham University
Abstract
Polar molecules combine long-range, anisotropic, and tunable dipole-dipole interactions with a rich internal structure of rotational and vibrational states. These properties have led to a number of proposed applications for quantum simulation [1], quantum computation [2], quantum chemistry [3], and the precision measurement of fundamental constants [4].
In this talk, I will first review the progress that has been made in the Durham bulk-gas RbCs experiments. Here, ultracold samples of ground-state RbCs molecules are produced by association from a pre-cooled mixture of Rb and Cs atoms [5]. We observe fast collisional loss of molecules from the optical trap, which we attribute to photo-induced chemical reactions mediated by ‘sticky’ molecule-molecule collisions [6]. By engineering magic optical traps, we have learned to encode second-scale coherences between the nuclear spins [7] and rotational states of the RbCs molecule [8], which in turn led to the observation of Hz-level dipole-dipole interactions in an ultracold thermal gas of molecules. Most recently, we have applied techniques borrowed from atomic quantum gas microscopy to perform improved imaging and addressing of our ultracold gas of RbCs molecules with single-molecule resolution [9].
Finally, I will outline progress made on a new experiment that I am constructing for the study of a new species of ultra-polar molecule RbAg. This molecule is predicted to have a large electric dipole moment of 9 Debye [10] and may be oriented in the laboratory frame at relatively low electric fields.
References:
[1] Blackmore et al., Quantum Sci. Technol. 4, 014010 (2019).
[2] Ni et al., Chem. Sci. 9, 6830-6838 (2018).
[3] Karman et al., Nat. Phys. 20, 722-729 (2024).
[4] DeMille et al., Nat. Phys. 20, 741-749 (2024).
[5] Molony et al., Phys. Rev. Lett. 113, 255301 (2014).
[6] Gregory et al., Phys. Rev. Lett. 124, 163402 (2020).
[7] Gregory et al., Nat. Phys. 17, 1149-1153 (2021).
[8] Gregory et al., Nat. Phys. 20, 415-421 (2024).
[9] Mortlock et al., Nat. Commun. 17, 518 (2026).
[10] Śmiałkowski and Tomza, Phys. Rev. A 103, 022802 (2021).