Applications
Quantum Computers
Anything a classical computer can do, a quantum computer can do equally well, or better. In some cases, such as factoring large numbers, a quantum computer can work orders of magnitude faster. This has serious implications in the realm of cryptography, as current encryption methods rely on a classical computer's inability to factor large numbers in anything close to resembling real time.
Since Quantum Computers work in parallel by nature, any problem that can be broken down into a parallel solution (or solutions) would run many times faster on such a device. Consider the realm of board games. In Chess, ultra-fast computers use brute force to search move after move, finding an optimal sequence of moves and then playing the first move in that sequence. If each branch of the main tree could be searched in parallel, then the speed at which the next "best" move is derived would increase drastically. A quantum approach may be applicable to the ancient board game Go.
The field of artificial intelligence (AI) may be profoundly influenced by quantum computers. Imagine a machine capable of calculating through several tasks, simultaneously, then coming up with the optimal solution to the problem, in real-time. With the advances that we have seen in the realm of speech recognition, coupled with the brutal computational power possessed by quantum machines, it is easy to foresee a day when we might talk to our computers ... and they'll respond intelligently.
Quantum entanglement gives quantum computers the ability to perform a "not" operation for free. Since the spin of two entangled electrons is fixed and opposite with respect to each electron, if one electron is set to a known spin (that is, up versus down), then the second electron must, instantly acquire the opposite spin of the first.
Related Sites
- The Quantum Computer
- Working with Light, Hewlett Packard
Quantum Communication
In an entangled system, the entanglement will persist until a measurement is made against one of the entangled parties. The act of measuring the system collapses the wave into a known state. This result would seem to end the possibility of using an entangled system for instantaneous communications.
Adiabatic perturbation is a subtle side-effect of an atom's motion. If two atoms were entangled, it may be possible to influence this slight motion without collapsing the wave into a known state. Since, by definition, an entangled state means that whatever happens to one particle happens to the other, slight perturbations may have a detectable correlated response.
Quantum Encryption
A great article on how quantum entanglement allows for unbreakable encryption can be found at:
Cracking Codes by Artur Ekert.
Quantum Teleportation
Quantum Teleportation is the act of transferring the complete quantum state from one particle to another. The process destroys the original, very much like the Star Trek teleporter devices.
Related Sites
