UC Berkeley

In this work, we present a novel method to couple any two vibrational modes of a single trapped ion, allowing energy to be swapped between the two modes. We use the scheme to perform ground state cooling and heating rate measurements of vibrational modes without direct optical access. This lessens experimental design constraints in trapped ion experi- ments, particularly in surface trap apparatus where optical access can be difficult.

We use a single ion as an electric-field noise sensor to study noise processes originating on the metallic surfaces of microfabricated ion traps. We show that realistic models of surface noise predict a specific polarization of the electric-field fluctuations relative to the trap geometry. In contrast, technical noise sources predict a different polarization direction and magnitude which can be inferred by electrostatic simulation of the trapping electrodes. We show that, by comparing heating rates of the two radial modes of a single trapped ion, one can determine whether technical noise sources are a significant contribution to heating. This is an important test for experiments aimed at studying surface noise effects. We also study dephasing due to surface noise, in which the electric potential curvature due to surface noise sources disturbs the phase of the ion motion. We measure the dephasing time for trapped ion motion. Using a noise model featuring dipolar noise sources, we probe the power spectrum of surface noise effects. These measurements, especially if repeated in a trap with smaller ion-electrode distances, may yield new insights as to the physical origin of surface noise effects.

We demonstrate a two-ion quantum simulation of vibrationally-assisted energy transfer, an important phenomenon in biochemical energy transfer. We show that the quantum simulator performs well when benchmarked against exact numerical simulation. We believe that our approach can be scaled to more complicated systems beyond the reach of classical simulation, and discuss several methods for extending the simulation.