Rydberg atoms in the vicinity of an optical nanofiber
Connecting atomic quantum registers via photonic channels into a quantum network is a promising way to achieve scalability, one of the crucial challenges in quantum technologies. Free-space scenarios considered so far are relatively easy to implement but suffer the drawback of strong losses. Optical nanowaveguides constitute an interesting alternative which offer strong transverse confinement of the field and hence strong coupling to atomic nodes in their vicinity. In particular optical nanofibers (ONFs) received much attention within the past two decades.
On the other hand, within the past two decades, the giant van der Waals interactions between Rydberg atoms and the associated blockade phenomenon have been key in many quantum information proposals, including atomic quantum registers and repeaters. In free-space, the energy shifts induced by the van der Waals interaction between two atoms prepared in levels of principal quantum numbers n > 50 and a few µm apart can be of the order of tens of GHz and effectively forbid their simultaneous resonant laser excitation. This blockade mechanism was employed to generate entanglement and perform gates in systems of individual atoms and atomic ensembles.
In this seminar, I shall present the theoretical results my collaborators and I obtained on the spontaneous emission and van der Waals interaction of rubidium atoms in the vicinity of a silica ONF [1,2] in view of building a Rydberg-atom-ONF interface. In particular, on the specific cases of S and P states, I shall analyze how the presence of the nanofiber and the symmetry breaking it induces modify the blockade and the anisotropy of the Rydberg-Rydberg interaction.
References
[1] E. Stourm, M. Lepers, J. Robert, S. Nic Chormaic, K. Mølmer, E. Brion, Spontaneous emission and energy shifts of a Rydberg rubidium atom close to an optical nanofiber, Phys. Rev. A 101, 052508 (2020).
[2] E. Stourm, M. Lepers, J. Robert, S. Nic Chormaic, K. Mølmer, E. Brion, Interaction of two Rydberg atoms in the vicinity of an optical nanofibre, New J. Phys. 25, 023022 (2023)