1 Why Quantum Computing?
Today’s computer architecture is built out of physical materials characterized by macroscopic properties. To maintain the current rate of progress in miniaturization we will soon have to use computing components characterized by microscopic properties.
An interesting strategy is to search for “computing predispositions". Where? Nature is an obvious “natural" candidate. As we will argue in this paper, quantum phenomena have an inherent computing capability waiting to be exploited.
Quantum computing is about computing with quantum systems (called quantum computers); it is not about quantum physics nor quantum chemistry. Quantum computing can not only offer a solution to the miniaturization problem, but much more. In fact, it is possible that quantum features can be used to accomplish computing tasks that are simply too hard for classical computers. Of course, these results come with a rather heavy price; for example, the logic of quantum computers is no longer the familiar classical logic, but the quantum logic (in which the distributivity is lost), bits (0 or 1) are replaced by qubits which can also exist in a superposition of 0 and 1, the classical operation of copying is unavailable, etc.
Finally, by changing the perspective, we can investigate quantum mechanics via quantum computing. For example, one can study experimentally quantum interference on a single quantum chip.
