A major obstacle in the way of miniaturisation of ion traps, desired for many aspects of trapped ion quantum information processing, is anomalous heating. This is heating of the ion’s motion via electric field fluctuations of the trap electrodes. These fluctuations are orders of magnitude stronger than expected from Johnson noise.
The reason for that is mostly associated with surface contamination/oxidation, however the actual mechanism behind this phenomenon is not understood so far, hence the heating is called “anomalous”.One of the ways to shed light onto the anomalous heating mechanism is the study of the ion’s heating rate dependence on the ion-electrode distance.
We have built a unique planar ion trap with tuneable ion-surface separation and measured this dependence directly for the first time. Our measurements yield a dependence in reasonable agreement with a power law of exponent -4 that is predicted by some theories.