Quantum Computing Concepts
To understand what makes a quantum computer unique, it is necessary to explore the background of the traditional classical computer to contrast it with its eventual quantum counterpart. Traditional computing theory is based on the work of Alan Turing, who created the concept of the Turing machine back in the late 1930s. The Turing machine is an abstract model designed to allow for study and creation of algorithms independent of physical computer hardware and software. It has been instrumental for deciding which types of problems are possible to solve on classical computers because on a conceptual level, a Turing machine can perform any calculation that a modern computer or supercomputer can (given enough time and memory). If a problem cannot be solved with a Turing machine, it cannot be solved with a classical computer.
However, the advent of quantum physics has revealed that the behavior of physical objects and systems does not adhere to classical physics at the molecular level. The study of abnormal behavior of particles at the atomic and subatomic level is where quantum physics began. It obviously did not begin solely with the goal of creating a faster computer, but there have been many possible applications—such as computation, encryption and quantum communication—that have stemmed from quantum physics research. But first we will examine the nature of quantum physics as it pertains to computers today.