Surface science for improved ion traps

Trapped ions are sensitive to electric-field noise from trap-electrode surfaces. This noise has been an obstacle to progress in trapped-ion quantum information processing (QIP) experiments for more than a decade. It causes motional heating of the ions, and thus quantum-state decoherence. This heating is anomalous because it is not easily explained by typical technical-noise sources. Experimental evidence of its dependence on ion-electrode distance, frequency, and electrode temperature points to the surface, rather than the bulk, of the trap electrodes as the origin. In this article, we review experimental efforts and models to help identify and reduce or eliminate the source of the anomalous heating. Recent progress to reduce the heating with in situ cleaning indicates that it may not be a fundamental limit to trapped-ion QIP. Moreover, the extreme sensitivity of trapped ions to electric-field noise may potentially be used as a new tool in surface science.