In this final lecture of this course we look back at the the key building block of the quantum computer: the qubit. Menno will set out the features of the four types of qubit platforms that have been discussed. What are their similarities, and how do these qubits differ from each other? Menno will also look forward to the second part of this course, where the other layers of the quantum computer will be discussed. What is needed to develop a fully functional quantum computer? And what is the approach to the development of a quantum internet?

Main takeaways

• Physical qubits can be controlled to a superposition state and coupled together to create entanglement. These principles are on the basis of a quantum computer and quantum internet.
• The qubit approaches you have been taught in this course are the spin qubit, the NV center qubit, the transmon qubit and the topological qubit. Which qubit platform is the best is not yet clear.
• Today’s quantum devices require individual electronics and connects for each and every qubit. Increasing these systems to large numbers will clearly require a different scaling law.
• This scalability aspect is described by the quantum extensibility of a system. Depending on all the resources, required at every position of the stack, a platform has the capability to scale up toward practical quantum information.
• In part 2 of this course we will introduce the other building blocks of a quantum computer and show you the vision of a full-stack future quantum computer. In addition, we will also introduce to you the foundations of a quantum internet. We hope to see you there!