A method of an on-demand beamsplitter for trapped-ion quantum computers

Quantum information processing using local modes of trapped ions has been applied to implementing bosonic quantum error correction codes and conducting efficient quantum simulation of bosonic systems. However, control of entanglement among local modes remains difficult because entanglement among resonant local modes is governed by the Coulomb interaction, which is not switchable. We propose a method of a beamsplitter for a trapped-ion architecture, where the secular frequency of each mode is dynamically controllable. The neighboring modes are far detuned except when the beamsplitter needs to be applied to them. We derive the analytical formula of the proposed procedure and numerically confirm its validity.