Experimental investigations of the resonant dipole-dipole interaction between cold Rydberg atoms

This talk will present our on-going effort to control the dipole-dipole interaction between cold Rydberg atoms. In our experiment, we trap individual atoms in two-dimensional arrays of optical tweezers separated by few micrometers and excite them to Rydberg states using lasers. The arrays are produced by a spatial light modulator, which shapes the dipole trap beam. We can create almost arbitrary geometries of the arrays [1]. We have measured the van der Waals interaction between two individual atoms [2], and show efficient Rydberg blockade in arrays of three atoms [3]. We have also demonstrated the control of the interaction between atoms with microwave and DC electric fields [4]. We observe in particular the coherent energy exchange between two atoms resulting from their dipole-dipole interaction [5]. This control of the interaction will find applications in quantum state engineering, quantum information and quantum simulation. \\[4pt] [1] F. Nogrette, H. Labuhn, S. Ravets, D. Barredo, L. B\'{e}guin, A. Vernier, T. Lahaye, A. Browaeys, ``Single- atom trapping in holographic 2D arrays of microtraps with arbitrary geometries,'' Phys. Rev. X \textbf{4}, 021034 (2014).\\[0pt] [2] L. Beguin, A. Vernier, R. Chicireanu, T. Lahaye, and A. Browaeys, ``Direct measurement of the van der Waals interaction between two single atoms,'' Phys. Rev. Lett. \textbf{110}, 263201 (2013). \\[0pt] [3] D. Barredo, S. Ravets, H. Labuhn, L. B\'{e}guin, A. Vernier, F. Nogrette, T. Lahaye, A. Browaeys, ``Demonstration of strong Rydberg blockade in three-atom systems with anisotropic interactions,'' Phys. Rev. Lett. \textbf{112}, 183002 (2014).\\[0pt] [4] S. Ravets, H. Labuhn, D. Barredo, L. B\'{e}guin, T. Lahaye, A. Browaeys, ``Coherent dipole-dipole coupling between two single atoms at a F\"{o}rster resonance'', Nature Physics \textbf{10}, 914 (2014).\\[0pt] [5] D. Barredo, H. Labuhn, S. Ravets, T. Lahaye, A. Browaeys, C. S. Adams, ``Coherent Excitation Transfer in a `Spin Chain' of Three Rydberg Atoms,'' arXiv:1408.1055