Atomic ions, confined in radio-frequency Paul ion traps, are a promising candidate to host a future quantum information processor. In this letter, we demonstrate a method to couple two motional modes of a single trapped ion, where the coupling mechanism is based on applying electric fields rather than coupling the ion's motion to a light field. This reduces the design constraints on the experimental apparatus considerably. As an application of this mechanism, we cool a motional mode close to its ground state without accessing it optically. As a next step, we apply this technique to measure the mode's heating rate, a crucial parameter determining the trap quality. In principle, this method can be used to realize a two-mode quantum parametric amplifier.
@article{arxiv.1405.5571,
title = {Two mode coupling in a single ion oscillator via parametric resonance},
author = {Dylan J Gorman and Philipp Schindler and Sankaranarayanan Selvarajan and Nikos Daniilidis and Hartmut Häffner},
journal= {arXiv preprint arXiv:1405.5571},
year = {2015}
}