What is a Quantum Computer?
(c)source
With today's technology we are able to squeeze millions of micron wide logic gates and wires onto the surface of silicon chips. It is only a matter of time until we come to a point at which the gates themselves will be made up of a mere handful of atoms. At this scale, matter obeys the rules of quantum mechanics. If computers are to become smaller and more powerful in the future, quantum technology must replace or reinforce what we have today.
Quantum computers aren't limited by the binary nature of the classical physical world. Instead, they depend upon observing the state of qubits (quantum bits) that may represent a one or a zero, a combination of the two, or that the state of the qubit is somewhere between 1 and 0. This "blending" of states is known as superposition.