We demonstrate tunable spin-spin couplings between trapped atomic ions, mediated by laser forces on multiple transverse collective modes of motion. A σxσx-type Ising interaction is realized between quantum bits stored in the ground hyperfine clock states of Yb ions. We demonstrate entangling gates and tailor the spin-spin couplings with two and three trapped ions. The use of closely-spaced transverse modes provides a new class of interactions relevant to quantum computing and simulation with large collections of ions in a single crystal.
@article{arxiv.0905.0225,
title = {Entanglement and Tunable Spin-Spin Couplings Between Trapped Ions Using Multiple Transverse Modes},
author = {K. Kim and M. -S. Chang and R. Islam and S. Korenblit and L. -M. Duan and C. Monroe},
journal= {arXiv preprint arXiv:0905.0225},
year = {2015}
}