In classical physics, the state of a bead stung on a fixed wire (as the one shown below), can be completely described by two numbers: its position and speed.

In quantum mechanics the bead's state is described by its wavefunction specified too by two numbers (magnitude and angle) but -unlike a classical bead- at every point along the wire. Since the number of points on the wire is infinite, the information needed to define the quantum state of the bead is much more than the one needed to define a classical state.

In conventional computers, the memory consists of storage locations that can be set to either "on" or "off". What would be the case if we devised a quantum computer? In a quantum computer, the processor switches can assume not only "up" and "down" positions -as in classical computers- but also an infinite number of other possibilities.Pieces of a quantum computer can interfere or become entangled, options that are not available to the components of classical computers.

Quantum computers might very well be "the next big thing" that will shape our future if scientists and engineers managed to harness the powerfull features of quantum mechanics. On the other hand, the whole idea may prove to be a "big bust" if quantum mechanics proved to be too expensive in the computer field.