Trapped ions are very suitable candidates for realizing quantum simulators because they provide us with excellent control over all quantum degrees of freedom: we can repeatedly and reliably prepare a quantum state, control its dynamic evolution, generate entangled states and carry out quantum measurements with high efficiency. In our experiment, we encode spin-1/2 particles into the electronic states of a string of trapped calcium ions. Laser beams are used to generate variable-range effective spin-spin interactions and a tightly focused laser beam allows for high-fidelity single-spin control.

In the first part of my presentation I will introduce the experimental setup and its capabilities, and explain how we engineer tunable-range spin-spin interactions. The second part focuses on properties of the realized interaction dynamics [1, 2], and presents a study of quantum transport under the influence of disorder and dephasing [3]. Finally, I discuss how we can apply our tunable-range interaction and single-qubit control to perform variational quantum simulation of lattice models with up to 20 sites [4].

[1] N. Friis, O. Marty, et al., PRX 8, 021012 (2018)

[2] T. Brydges, A. Elben et al., Science 364, 260 (2019)

[3] C. Maier et al., Phys. Rev. Lett. 122, 050501 (2019)

[4] C. Kokail, C. Maier, R. van Bijnen et al., Nature 569, 355 (2019)