DC: Depth Control on Quantum Classical Circuit

Abstract

The growing prevalence of near-term intermediate-scale quantum (NISQ) systems has brought forth a heightened focus on the issue of circuit reliability. Several quantum computing activities, such as circuit design and multi-qubit mapping, are focused on enhancing reliability via the use of different optimization techniques. The optimization of quantum classical circuits has been the subject of substantial research, with a focus on techniques such as ancilla-qubit reuse and tactics aimed at minimizing circuit size and depth. Nevertheless, the reliability of bigger and more complex circuits remains a difficulty due to potential failures or the need for time-consuming compilation processes, despite the use of modern optimization strategies. This study presents a revolutionary Depth Control (DC) methodology that involves slicing and lowering the depth of conventional circuits. This strategy aims to improve the reliability and decrease the mapping costs associated with quantum hardware. DC provides reliable outcomes for circuits of indefinite size on any Noisy Intermediate-Scale Quantum (NISQ) system. The experimental findings demonstrate that the use of DC leads to a substantial improvement in the Probability of Success Threshold (PST), with an average increase of 11x compared to non-DC baselines. Furthermore, DC exhibits a notable superiority over the next best outcome by ensuring accurate outputs with a considerable margin. In addition, the utilization of Design Compiler (DC) enables the execution of mapping and routing optimizations inside a polynomial-time complexity, which represents an advancement compared to previously suggested methods that need exponential time.