TECHNOLOGY: Quantum Computing

Neurons in the human brain can muster out about 1000 operations per second - many orders of magnitude slower than the trillions of operations per second harnessed by today's supercomputers. Despite this huge disadvantage in computing power, we are able distinguish the faces of our relatives and recognize speech much better than modern supercomputers. The reason that modern computers fail to efficiently perform these tasks is their inability to process in a parallel manner. While our brains work with billions of neurons firing together to convey complex messages, computers can only process serially, reading simple binary 1/0 bits and passing them through "logic" gates. This limitation of computers results in problems of recognition, pattern identification, and co processing that would take modern supercomputers billions of years to solve serially. However, quantum computers of the future offer the possibility of a supercomputer with parallel processing powers surpassing those of the human brain.

The basic unit of the quantum computer is the qubit which, unlike the binary bits of computers, can exist in more than two states: 0, 1, and a variety of superpositions of the two opposite states. This superposition state is a phenomenon of quantum mechanics stating that if we cannot observe the true state of the qubit, it exists as both states with a probability being attached to each state. While this may seem strange, it is fundamental aspect of quantum mechanics that has been experimentally demonstrated. A site from Caltech give a good explanation of this principle and its application to quantum computers. These superpositions allow quantum computers to perform operations on each state simultaneously, allowing for parallel processing.

Another interesting phenomenon of quantum mechanics is the entanglement phenomenon, which states that certain atoms may become "entangled" so that the state of one atom is directly tied to the state of another. This mysterious relationship is instant and can theoretically span an infinite amount of distance or barriers. Moreover, the entanglement can be used to connect multiple qubits with invisible "wires" that would ideally eliminate some of the major wiring and heat loss issues of modern computers.

While quantum computers hold a lot of promise in their parallel processing powers, the technology is still far off. One issue is that of decoherence, which is the tendency of a quantum state to decay after interaction with outside environments. This creates the need for extremely isolated systems with very stable bits, and has been a major obstacle for quantum computer manufacturers.

The applications for quantum computers are very promising. First, computers with parallel processing could immensely aid in artificial intelligence modeling. Parallel processing would allow us to create computers that "think" much like our brain allows us to think, resulting in a much more authentic simulation. Second, quantum computers would give us a more effective ability to model nanoscale processes. At the nanoscale, traditional Newtonian physics frequently gives way to quantum mechanics. While serial computers are unable to solve the quantum equations needed to model physical objects at a nanoscale, quantum computers are built to easily solve them. Quantum computers could support software similar to CAD in order to model products on the nanoscale.

D-Wave is a company that has recently been making news for their production of a very simple quantum computer prototype.