The Quantum of Computing

Modern digital computers are smaller, faster and cheaper than their ancestors. However, although computers have become vastly more efficient at accomplishing their work, the work remains essentially the same. The work in question involves the manipulation of bits of information. The term "Bit" stands for "Binary Digit". Binary is a numbering system that represents values as sequences of zero's and one's. For example the number 13 can be represented by the sequence 1101.

Quantum Computing is an emerging field in computer science that differs fundamentally from digital computing in that it's basic unit of computation is not the Bit, but the Qubit. Unlike a Bit, which exists in a state of 0 or 1, a Qubit can exist as 0, 1, or simultaneously as both 0 and 1. This unusual property is possible due to an effect known as single-particle interference.



Single-particle interference can be visualized by imagining a laser firing a stream of photons into a light splitter. The splitter sends half the photons left and allows the rest to continue straight through. Given this information you might expect that each photon has an equal probability of traveling left or straight. However, quantum mechanics predicts that each photon travels both paths simultaneously.



Getting computers to do two things at once, or "Multitask" has long been the goal of computer scientists. Most household computers today appear to do several things at once, but generally this is an illusion created by making the computer switch between lots of different small tasks very quickly. Quantum Computers however, are capable of true multitasking, performing enormous parallel computations.

Theoretically the computers we have today can simulate the function of quantum computers. So why do we need quantum computers? Well although modern computers can theoretically simulate the function of quantum computers, it would be computationally too expensive to do so. Simulating a quantum computer with even a few dozen qubits is well beyond the capability of any computer made today.

The power of quantum computing should not be underestimated. In the future it may allow computer models to be advanced enough to predict tsunamis, with the potential to save thousands of lives. They may also be able to model our entire climate and ecosystem, helping us to reverse the damage of climate change and perhaps save the planet.