Skip main navigation

Superconducting systems/超電導システム

Superconducting systems/超電導システム
I am here again at the University of Tokyo with Professor Yasunobu Nakamura, an expert on superconducting qubit. Professor Nakamura, tell us about devices you are building. Okay, we are trying to build a small quantum information processing system using superconducting qubits. So there we put several superconducting qubits as an array and then control them to manipulate the quantum state to demonstrate simple quantum information processing. How do you execute one and two qubit gates using superconducting system?
Yes, so as you know, it is very important to apply very precise control on superconducting qubit and for that we are using microwave pulses typically in a timescale of 10 nanosecond to 100 nanosecond to implement quantum gate for single qubit control and 2 qubit gate. How do you make your superconducting chip? Yes, similarly to silicon technology, we use lithography for making superconducting devices, so like optical lithography and electron beam lithography are used to create superconducting chips in a tiny scale. Okay, what is unique about your approach?
Okay, so now we would like to put superconducting qubits in array in a two-dimensional way, so qubits will be arranged on a small chip in a two-dimensional array and then we would like to control the quantum state to implement simple quantum information processing. Okay. Tell us what’s the challenge for building large scale quantum system using your technique.
Okay, the important thing is that we need to control many qubit, so for that we need many wiring to control and read out the signal and that is quite challenging because chip – on the chip qubits are densely aligned and then there are not much – there is not much space left for the wiring, so the arranging all the wiring properly and also sending and read out the signal properly is quite challenging. That’s our near term target. Okay, thank you professor Nakamura.



superconducting qubit rig, from Professor Nakamura's laboratory 図は中村泰信教授により提供されました。


stages for cooling and controlling a superconducting qubit, from Professor Nakamura's laboratory 図は中村泰信教授により提供されました。


Al block with a single superconducting qubit, from Professor Nakamura's laboratory 図は中村泰信教授により提供されました。






design for a scalable silicon superconducting chip from Professor Nakamura's laboratory 図は中村泰信教授により提供されました。


This article is from the free online


Created by
FutureLearn - Learning For Life

Our purpose is to transform access to education.

We offer a diverse selection of courses from leading universities and cultural institutions from around the world. These are delivered one step at a time, and are accessible on mobile, tablet and desktop, so you can fit learning around your life.

We believe learning should be an enjoyable, social experience, so our courses offer the opportunity to discuss what you’re learning with others as you go, helping you make fresh discoveries and form new ideas.
You can unlock new opportunities with unlimited access to hundreds of online short courses for a year by subscribing to our Unlimited package. Build your knowledge with top universities and organisations.

Learn more about how FutureLearn is transforming access to education