Current Progress and Remaining Challenges in Development of On-chip Ion Traps

We report on an ion-shuttling experiment which is one of the core technologies in large scale ion-trap quantum computers. By controlling voltages applied to five pairs of electrodes in an on-chip ion trap, we have demonstrated shuttling of a single calcium ion. Besides the experimental result, we introduce discussion of the relation between ion motion and the condition of surface of trap electrodes and discuss the vacuum techniques which are required for scaling up of ion-trap quantum computers.