A Fast Algorithm for Synthesis of Quantum Reversible Logic Circuits

Reversible logic finds many applications,especially in the area of quantum computing. Quantum reversible logic circuits are basic elements in quantum computer construction. Synthesis of quantum reversible logic circuits means to automatically construct desired quantum reversible logic circuit with minimal quantum cost. The authors absorb different ideas of reversible logic circuits synthesis and present a novel and efficient algorithm which can automatically derive the positive polarity Reed-Muller expansion (RM). A solution space tree is constructed to create quantum reversible logic circuits. Firstly,floor traversal is applied globally,and depth-first search is used locally. Secondly,according to the technique of template optimization,the bound function is constructed,which can rapidly prune the branches with no or nonoptimal result. Thirdly,factors of RM are first considered,therefore the algorithm can effectively construct optimal result and saves computational cost significantly. Judging by the internationally recognized reversible functions of three variables,the proposed algorithm not only synthesizes all optimal reversible functions,but also runs extremely faster than others of the same kind.