Reversible computing and cellular automata — a survey ∗ ( Preliminary draft )

Reversible computing is a paradigm where computing models are so defined that they reflect physical reversibility, one of the fundamental microscopic physical property of Nature. In this survey/tutorial paper, we discuss how computation can be carried out in a reversible system, how a universal reversible computer can be constructed by reversible logic elements, and how such logic elements are related to reversible physical phenomena. We shall see that, in reversible systems, computation can be often carried out very different manner from conventional (i.e., irreversible) computing systems, and even very simple reversible systems or logic elements have computationor logical-universality. We discuss these problems based on reversible logic elements/circuits, reversible Turing machines, reversible cellular automata, and some other related models of reversible computing.