Per-gate noise vulnerability of quantum algorithms: A systematic benchmarking study across multiple error channels
The performance of quantum algorithms on near-term devices is heavily constrained by hardware noise, yet systematic comparisons of algorithmic vulnerability across diverse noise types remain limited. In this study, we benchmark three representative algorithms: quantum teleportation, Grover’s search, and the Quantum Approximate Optimization Algorithm (QAOA), under depolarizing, amplitude damping, phase damping, and thermal relaxation channels. Using exact density-matrix simulations, we characterize algorithmic performance by evaluating state fidelity decay as a function of noise strength. To enable fair, structure-aware comparisons across circuits of varying depths, we introduce a novel metric, the per-gate decay rate. Our analysis reveals that teleportation exhibits the lowest per-gate vulnerability, whereas Grover’s algorithm demonstrates substantially larger, super-linear decay driven by its repeated oracle–diffuser architecture. QAOA displays intermediate and stable noise resilience across system sizes. Finally, we validate our simulation framework through hardware experiments on an IBM Heron processor, demonstrating strong agreement with theoretical predictions (Pearson’s correlation coefficient r = 0.981). This work establishes a quantitative, structure-aware framework for assessing circuit-level noise sensitivity and offers actionable insights for algorithm selection in the noisy intermediate-scale quantum era.