Accuracy analysis of the parallel composition for the block diagram based reliability assessment of quantum circuits

Simulation cannot be applied for complex quantum circuits' reliability analysis. Therefore, mixed simulation - analytical techniques should be applied in order to evaluate the reliability of quantum devices. One of the most used analytical methods is represented by the reliability block diagrams (RBD). This paper presents the accuracy estimates analysis for the parallel composition in the RBD based reliability estimation for quantum circuits. We analyze the influence of the idle qubit block size on and the influence of the idle qubit interleaving on the relative error. The obtained results will be used in accuracy estimation of the mixed simulation-RBD methodology for reliability assessment of quantum circuits.