Quantum simulation and quantum information in segmented ion traps
Dr. Michael Johanning (Universität Siegen)

Laser cooled ions in segmented traps are one of the hot candidates for scalable quantum information processing. The experimental quantum optics group in Siegen pursues an approach, where an inhomogeneous magnetic field lifts the degeneracy of ionic Zeeman resonances and allows for selective microwave manipulation of single ions. Furthermore, the gradient creates an effective long range coupling between ions, mediated by the Coulomb repulsion (MAgnetic Gradient Induced Coupling - MAGIC).

In one 3D and one planar trap geometry, we use the segmentation of the axial potential to tailor the axial potential. The required set of independent stable low noise voltages is generated by a multi-channel arbitrary waveform generator developed in our group. The potentials created in this way allow to shuttle ion strings and we investigate the internal state coherence of hyperfine qubits under such operations. The axial potential can be made substantially anharmonic, e.g. for splitting and merging of ion strings and allows to tune trap frequencies and coupling constants. This can be used to create coupling patterns which, together with microwave manipulation, create effective Hamiltonians which exhibit Long Distance Entanglement (LDE). We also demonstrate the application of a segmented gradient in our planar trap and discuss future applications and possible upgrades of our experiments.