Title: Study of Electric Field Noise from Carbon Contamination above a Surface Ion Trap

Abstract: 
Ion trap systems are the most promising platform for quantum information processing (QIP). Due to extreme sensitivity to electromagnetic fields generated by trap surfaces and materials environments, their practical performance gets hindered. One such important error source for the high-fidelity operation of ion trap quantum processors is electric field noise (EFN). This noise is orders of magnitude higher than expected from known noise sources. Cleaning the trap surface reduces the measured surface contamination and reduces the measured noise, suggesting contamination is responsible for a significant portion of the noise. Carbon is one of the main surface contaminants observed on nearly all trap surfaces. At least two studies have correlated the amount of surface carbon contamination with the amount of measured noise during a cleaning cycle. However, different cleaning methods that all successfully remove contamination lead to very different reductions in noise, suggesting the cleaning methods modify the surface in ways besides removing material. To study the effect of carbon contamination on surface noise while avoiding additional effects cleaning may have on the surface, our current experiment uses electron-beam-induced deposition (EBID) using an ethylene precursor gas to deposit several carbon monolayers onto the surface of an ion trap. Initial noise measurements before and after deposition suggest an order-of-magnitude increase in noise due to carbon contamination.