A recursive method for synthesizing quantum/reversible quaternary parallel adder/subtractor with look-ahead carry

Multiple-Valued quantum logic Circuits ire a promising choice for future quantum computing technology since they have several advantages over binary quantum logic Circuits. Adder/subtractor is the major component of the ALU of a Computer and is also used in quantum oracles. In this paper, we propose a recursive method of hand synthesis of reversible quaternary full-adder circuit using macro-level quaternary controlled gates built oil the top of ion-trap realizable 1-qudit quantum gates and 2-qudit Muthu-krishnan-Stroud quantum gates. Based on this quaternary full-adder circuit we propose a reversible circuit realizing quaternary parallel adder/subtractor with look-ahead carry. We also show the way of adapting the quaternary parallel adder/subtractor Circuit to an encoded binary parallel adder/subtractor circuit by grouping two qubits together into quaternary qudit values. (c) 2008 Elsevier B.V. All rights reserved.