A novel reversible two's complement gate (TCG) and its quantum mapping

Reversible Logic has been an emerging topic of research for the last decade and has witnessed a substantial amount of work related to synthesis algorithms, optimization techniques and Boolean circuits. Considerable amount of reversible binary arithmetic designs have been proposed. 2's complement addition forms a fundamental arithmetic operation. This present communication proposes a novel reversible Two's Complement Gate (TCG) which can directly constitute a reversible adder/subtractor design. We provide the Toffoli representation of the gate for its plausible quantum realization. We also provide the quantum metric analysis for evaluation of our proposed gate. The proposed gate has also been implemented using Quantum-Dot Cellular Automata. Comparison with an existing proposal in literature has been done and the TCG gate has been observed to excel over the counterpart.