Theoretical investigation of electric-field noise emanating from vibrational adatoms

Electric-field noise stemming from surface adsorption of atoms serves as the main factor of anomalous motional heating and decoherence for trapped ions confined in harmonic potentials of surface-electrode traps. However, this also provides a possible way for ions playing as nanosensors to detect surface defects and explore the mechanism of noise. Taking monatomic vibrations on the surface into account, here we calculate the electricfield noise and discuss its spectral properties by utilizing density-functional theory and the incoherent master equation with fitting parameters. We find that most adatoms lead to universal spectral intensity and frequency scaling. Particularly, we discover a colored feature for the weak-binding Ar adatom with the increase of the temperature, which can be attributed to the anharmonic potential and high-lying vibrational states. Our results could be helpful for understanding the mechanism of the surface noise and developing efficient noise-detection methods.