A nearest neighbor quantum cost metric for the reversible circuit level

Motivated by the prospects of quantum computation, the design of quantum circuits received significant attention in the recent past. Due to the complex representation of the underlying quantum mechanical phenomena, a two-stage design flow was established in which the desired functionality is first realized in terms of a reversible circuit and, afterwards, mapped into an equivalent quantum circuit. This paper proposes a new metric for estimating nearest neighbor cost at the reversible circuit level. Research works are mostly carried out considering nearest neighbor constraints at the quantum circuit level. Various quantum gate libraries and mapping schemes have been reported in the literature to realize the circuit operation at quantum level. One such mapping scheme exploiting a well established quantum gate library (NCV) is explored in defining the cost metric. Experimental evaluations confirmed both the accuracy as well as the applicability of the proposed metric.