Seminarium Optyczne

Radiofrequency (RF) traps for atomic ions offer a unique level of control accompanied by e.g. long coherence times, excellent state preparation and readout efficiencies and record-worthy qubit gate fidelities. However, in some applications, most notably in investigations of ultracold ion-atom interactions, the presence of RF fields and the resulting driven motion has also been shown to be responsible for undesired or detrimental effects. In the case of ion-atom collisions, they manifest themselves as the so-called micromotion-induced heating [1]. The latter invokes restrictions with respect to the accessible collision energies which so far have been limited to the range of mK and above for the most available ion-atom combinations [2]. I will discuss an alternative experimental approach to studying ion-atom interactions aiming to combine several key features of ions, foremost their long-range Coulomb interaction, with the versatility of optical traps. This technique known as optical ion trapping allows for confining single ions or ion Coulomb crystals without RF fields [3] and offers comparatively long lifetimes on the order of seconds [4]. I will present our most recent results demonstrating sympathetic cooling of an ion immersed into an ensemble of ultracold atoms overlapped in a set of optical dipole traps [5], and discuss their potential applications in several fields ranging from quantum chemistry to novel quantum simulations. [1] M. Cetina, A.T. Grier, V. Vuletic, Phys. Rev. Lett. 109, 253201 (2012)[2] Härter, J.H. Denschlag, Contemp. Phys. 55(1), 33–45 (2014);M. Tomza, K. Jachymski, R. Gerritsma, A. Negretti, T. Calarco, Z. Idziaszek, P.S. Julienne, Rev. Mod. Phys. 91, 035001 (2019)[3] J. Schmidt, A. Lambrecht, P. Weckesser, M. Debatin, L. Karpa und T. Schaetz, Physical Review X 8, 021028 (2018)[4] A. Lambrecht, J. Schmidt, P. Weckesser, M. Debatin, L. Karpa and T. Schaetz, Nature Photonics 11, 704 (2017)[5] J. Schmidt, P. Weckesser, F. Thielemann, T. Schaetz, and L. Karpa, arXiv:1909.08352