The bit is the fundamental unit of storage in a classical computer, similarly, the basis of quantum computation is a qubit. The qubit is similar to a bit in that when measured its value will be either 0 or 1. It differs primarily in what it is doing when it is not being measured. In particular, a qubit can exist in any superposition of the 0 and 1 state simultaneously. When a qubit in such a state is measured the superposition will be destroyed. It will be found to be uniquely in the 0 or 1 state with some probability for each, determined by the particulars of the superposition prior to the measurement. [WC98]