Here is a nice preprint comparing some of the methods of realizing qubits, including neutral atoms, ions, superconducting circuits, etc.
I’m about to give a short talk on this very topic to an undergraduate Computer Science class. The talk will serve two purposes, it will be an introduction to the myriad of different methods by which qubits and quantum computers can actually be realised, and secondly it will be a nice insight into some of the things that experimentalists have to worry about when they are actually building quantum computers. Here is the talk overview:
Models of quantum computation
Ion traps – Optical photons / Neutral atoms – NMR – Superconducting circuits – Nanomechanical resonators
Example of operation
The Bloch sphere – The density matrix
Decoherence + limitations
The DiVincenzo criteria – Measuring T1 and T2 – Sources of decoherence
Unfortunately I won’t be recording this one so no videos this time. Boo.