(Oct 11) Trapped-ion quantum memory and monolithic ion-trap system

In this seminar, I’d like to discuss two experimental results that recently have been conducted and developed in our lab. Firstly, I present the observation of coherence time over 10 minutes for a single qubit system in a single ion. For the ensemble of qubits, there have been reported about ten minutes and hours of coherence time in trapped ion systems [1] and in solid state systems [2], respectively.  For a single qubit, however, the longest coherence time reported is less than one minute [3], which was realized in trapped ion systems, to our knowledge. The main limitation of the coherence time in the trapped ion system comes from the heating of the ion without cooling. We overcome the limit by realizing a hybrid trapped ion system, which composes of qubit and cooling ion. Secondly, I’d like to talk a newly developed three-dimensional monolithic radio frequency (RF) trap has a deep confining potential and can be extended to contain multiple zones similar to two-dimensional surface traps. The basic structure of the trap is analogous to the combination of the structure of three-layer trap [4] and the symmetric trap [5], but the post-processing assembly of multi-layers is not required in the fabrication. On a single layer of alumina plate, we implement RF electrode and twenty DC electrodes. We successfully load ions in the trap. We report the full controllability of the trap such as axial and radial trap frequencies, heating rates and compare them to the theoretical expectations. This trap can hold ions in two-dimensional configuration, which open the possibility of performing the quantum simulation in 2D materials.