Measuring anomalous heating in a planar ion trap with variable ion-surface separation

TL;DR

This study directly measures how the anomalous heating rate of trapped ions depends on their distance from a surface, finding a power-law relationship with an exponent of approximately -3.79.

Contribution

The paper provides the first direct experimental measurement of the ion-surface separation dependence of anomalous heating in a planar ion trap.

Findings

Heating rate follows a power law with ion-surface separation.

Measured exponent of the power law is approximately -3.79.

Results improve understanding of ion-surface interactions in traps.

Abstract

Cold ions trapped in the vicinity of conductive surfaces experience heating of their oscillatory motion. Typically, the rate of this heating is orders of magnitude larger than expected from electric field fluctuations due to thermal motion of electrons in the conductors. This effect, known as anomalous heating, is not fully understood. One of the open questions is the heating rate's dependence on the ion-electrode separation. We present a direct measurement of this dependence in an ion trap of simple planar geometry. The heating rates are determined by taking images of a single $^{172}$Yb${^+}$ ion's resonance fluorescence after a variable heating time and deducing the trapped ion's temperature from measuring its average oscillation amplitude. Assuming a power law for the heating rate vs. ion-surface separation dependence, an exponent of -3.79 $\pm$ 0.12 is measured.