In quantum computing, qubit or quantum bit, is a unit of quantum information—the quantum analogue of the classical bit.
A qubit is a two-state quantum-mechanical system such as the polarization of a single photon: here the two states are vertical polarization and horizontal polarization. In a classical system, a bit would have to be in one state or the other, but quantum mechanics allows the qubit to be in a superposition of both states at the same time, a property which is fundamental to quantum computing.
Perhaps I should have uploaded this one to Bits & Bytes’ specific Tumblr account, but I’m still trying to keep a certain degree or order over there (I will post it when the time comes, I guess), so right now I’ll leave this here.
This is the english version of my farewell to Satoru Iwata. Nothing else to say, really.