The NSA says :
"All microprocessor firms have turned to multiple cores and reduced power in efforts to improve performance..... Alternatives to CMOS must therefore be found. Quantum computers, or Superconducting Rapid Single Flux Quantum (RSFQ) technology, is where they are placing their bets.
A quantum computer is a device for computation that makes direct use of quantum mechanical phenomena, such as superposition and entanglement, to perform operations on data.
A classical computer has a memory made up of bits, where each bit represents either a one or a zero. A quantum computer maintains a sequence of qubits. A single qubit can represent a one, a zero, or, crucially, any quantum superposition of these; moreover, a pair of qubits can be in any quantum superposition of 4 states, and three qubits in any superposition of 8. In general a quantum computer with n qubits can be in an arbitrary superposition of up to 2n different states simultaneously (this compares to a normal computer that can only be in one of these 2n states at any one time). A quantum computer operates by manipulating those qubits with a fixed sequence of quantum logic gates. The sequence of gates to be applied is called a quantum algorithm.
Lost yet?
If you like reading technical journals, read this from the NSA:
http://www.nitrd.gov/pubs/nsa/sta.pdf
And check out a real Quantum computer in a super-cooled environment: The
DWave Quantum Computer.
http://nextbigfuture.com/2008/11/dwa...-pictures.html
Just amazing.