Realization of geometric Landau-Zener-Stuckelberg interferometry

We report an experimental realization of the geometric Landau-Zener-Stuckelberg (LZS) interferometry proposed by Gasparinetti et al. [Phys. Rev. Lett. 107, 207002 (2011)] in a single-trapped-ion system. Unlike those in a conventional LZS interferometer, the interference fringes of our geometric interferometer originate solely from a geometric phase. We also observe the robustness of the interference contrast against noise or fluctuations in the experimental parameters. Our scheme can be applied to other complex systems subject to relatively large errors in system control.