Introduction: trapped-ion quantum technology
Trapped-ion quantum technology utilizes atomic ions levitated in a vacuum for quantum technology applications by controlling them with electromagnetic waves. As a blueprint, a distributed architecture in which small trapped-ion quantum computers are photonically interconnected. In order to realize such an idea, trapped-ion quantum technology is facing major challenges in three different layers: trapped-ion quantum node, ion-photon interface and system for photonic interconnection.
Distributed architecture of trapped-ion quantum computer
Modularizing trapped-ion quantum node utilizing nanophotonics
Photonically integrated ion trap
Ion-trap quantum technology relies inevitably on laser control of quantum states. Conventionally, a bunch of mirrors and lenses are rigidly mounted on a large optical table to implement one quantum node, however, this way of constructing large-scale trapped-ion quantum computer is not realistic. Photonically integrated ion trap is an attempt to transform this kind of bulk optics into nano- or micro-scale photonic circuit on a mm-scale chip. By doing so, we are aiming at realizing reproducible "plug-and-play" ion trap that will be advantageous in scaling up the number of photonically interconnected ion traps.
Stable ion-photon interface on a linear trap
Atomic ions fit relatively nicely with photonic quantum technology for their optical transitions. By putting an ion inside the optical cavity so that it interacts strongly with the optical cavity, an ion-photon interface is intensely studied. Conventional implementation of them are based on the three-dimensional ion traps that does not afford manipulating multiple ions in a trap, and our motivation is to implement microscale optical cavity on a linear trap to make an ion-photon interface that is more versatile in the trapped-ion quantum technology.
Ion-photon interface on a linear trap
Implementation of quantum network and remote quantum gate
Schematics of photonic interconnection and control hardwares of ion traps
Main idea of quantum networking is to encode or convert the quantum information into photons and then make them transferred and/or interfere over remote quantum nodes to proceed the quantum information processing. Its applications range from distributed quantum computing indispensable for the trapped-ion quantum technology, quantum sensing and quantum communication. These are still in the first stage of their implementations, where trapped-ion platform has served as a powerful playground.
In our group, we aim at implementation of elementary quantum network using trapped-ion quantum nodes in close collaboration with Quantum Internet Tase Force (QITF), Japan. We are constructing the quantum nodes on the premise that aforementioned technologies will be installed to further promote the trapped-ion based qunatum networking.