On the Detection of Missing-Gate Faults in Reversible Circuits by a Universal Test Set

Logic synthesis with reversible circuits has received considerable interest in the light of advances recently made in quantum computation. Implementation of a reversible circuit is envisaged by deploying several special types of quantum gates, such as k-CNOT. Newer technologies like ion trapping or nuclear magnetic resonance are required to emulate quantum gates. Although the classical stuck-at fault model is widely used for testing conventional CMOS circuits, new fault models, namely, single missing-gate fault (SMGF), repeated-gate fault (RGF), partial missing-gate fault (PMGF), and multiple missing-gate fault (MMGF), have been found to be more suitable for modeling defects in quantum k-CNOT gates. In this paper, it is shown that in an (n times n) reversible circuit implemented with k-CNOT gates, addition of only one extra control line along with duplication each k-CNOT gate yields an easily testable design, which admits a universal test set of size (n +1) that detects all SMGFs, RGFs, and PMGFs in the circuit.