The n-bit quantum adder
Quantum computer requires requires quantum arithmetic. The sophisticated design of a reversible arithmetic logic unit (reversible ALU) for quantum arithmetic has been investigated in this letter. We provide explicit construction of reversible ALU effecting basic arithmetic operations. By provided the corresponding control unit, the proposed reversible ALU can combine the classical arithmetic and logic operation in a reversible integrated system. This letter provides actual evidence to prove the possibility of the realization of reversible Programmable Logic Device (RPLD) using reversible ALU.
Reversible computing is a model of computing where the computational process to some extent is reversible, i.e., time-invertible. A necessary condition for reversibility of a computational model is that the transition function mapping states to their successors at a given later time should be one-to-one. Reversible computing is generally considered an unconventional form of computing.
There are two major, closely-related, types of reversibility that are of particular interest for this purpose: physical reversibility and logical reversibility
Probably the largest motivation for the study of technologies aimed at actually implementing reversible computing is that they offer what is predicted to be the only potential way to improve the energy efficiency of computers beyond the fundamental von Neumann-Landauer limit of energy dissipated per irreversible bit operation.
The sophisticated design of a reversible arithmetic logic unit (reversible ALU)
Conclusions: Arithmetic Logic Unit (ALU) for the Programmable Logic Device (RPLD) has been presented in this letter in a reversible way. The reversible version ALU aims at eliminating the energy dissipation effecting by the irreversible action of classical computer. All the suggested operations provided by the proposed ALU are self-inverse or have an easy inverse operation. Also from another perspective, the realization of an efficient reversible ALU shows that a reversible programmable computing device is possible. But it is still a question that the general quantum operations, such as Hadamard, phase shift and rotation by π/4, etc, can not be integrated into the proposed reversible ALU until now