A quantum register is just a group of qubits, all part of the same
quantum mechanical system. Just as a *n* bit register is capable of
representing 2^{n} distinct values, so too will a *n* bit quantum
register assume one of 2^{n} basis states when measured. [WC98]

A quantum algorithm consists of a sequence of operations on that register, to transform it into a state which, when measured, yields the desired result with high probability.

Note that a *n* bit quantum register can store an exponential amount
of information. The register as a whole can be in an arbitrary
superposition of the 2^{n} base states which it can be measured to
be in. While in this superposition, and computation applied to the
register will be applied to each component of the superposition, this
behavior follows from the linearity of operators on quantum mechanical
systems. This behavior, called *quantum parallelism* is the basis
for most quantum algorithms.