The paper "Novel Reversible CLA, Optimized RCA and Parallel Adder/Subtractor Circuits"

The paper entitled "Novel Reversible CLA, Optimized RCA and Parallel Adder/Subtractor Circuits" was published by Serbian Journal of Electrical Engineering in October 2020. This paper proposes reversible circuit designs of the three most commonly used adders: carry look-ahead adder (CLA adder), ripple carry adder (RCA adder), and parallel adder/subtractor. The n-bit reversible CLA adder, called CLA-GH, is designed using the Peres and Fredkin gates. The n-bit optimized reversible RCA adder, called ORCA-GH, is designed using the reversible circuit of a parity-preserving reversible full adder. Both circuits reduce the quantum cost. However, the ORCA-GH circuit also improves the number of constant inputs. Furthermore, the n-bit reversible parallel adder/subtractor, called PAS-GH, is designed using the Feynman, Peres, and Fredkin gates. It decreases the number of garbage outputs and quantum cost. The transistor realizations of the CLA-GH and PAS-GH circuits are provided accordingly. The evaluation results indicate that the proposed circuits surpass the existing works in all figures of merit.

You can obtain more information about this paper via the link.