Publications

Electric-field noise from carbon-adatom diffusion on a Au(110) surface: First-principles calculations and experiments

Kim, E.; Safavi-Naini, A.; Hite, D.A.; McKay, K.S.; Pappas, D.P.; Weck, Philippe F.; Sadeghpour, H.R.

The decoherence of trapped-ion quantum gates due to heating of their motional modes is a fundamental science and engineering problem. This heating is attributed to electric-field noise arising from the trap-electrode surfaces. In this work, we investigate the source of this noise by focusing on the diffusion of carbon-containing adsorbates on the surface of Au(110). We show by density functional theory, based on detailed scanning probe microscopy, how the carbon adatom diffusion on the gold surface changes the energy landscape and how the adatom dipole moment varies with the diffusive motion. A simple model for the diffusion noise, which varies quadratically with the variation of the dipole moment, predicts a noise spectrum, in accordance with the measured values.