Fidelity-Based Robustness Margins for Finite-Time Quantum Control

• URL: http://arxiv.org/abs/2608.03698v1
• Date: Tue, 04 Aug 2026 14:01:42 GMT
• Title: Fidelity-Based Robustness Margins for Finite-Time Quantum Control
• Abstract summary: We develop a structure-specific fidelity-threshold margin for finite-dimensional closed quantum systems under piecewise-constant coherent control.<n>Recentering this certificate produces an iterative one-dimensional method that takes certified safe steps toward the first fidelity-threshold boundary.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: We develop a structure-specific fidelity-threshold robustness margin for finite-dimensional closed quantum systems under piecewise-constant coherent control. A scalar physical parameter may perturb the drift, a control Hamiltonian, or another declared Hamiltonian component across the control horizon. A differential sensitivity bound for trace-amplitude gate fidelity yields a threshold-dependent Lipschitz constant on the connected safe parameter component and hence a certified finite perturbation radius. Recentering this certificate produces an iterative one-dimensional method that takes certified safe steps toward the first fidelity-threshold boundary in either parameter direction. A three-qubit gate-control example shows that these finite margins vary by up to a factor of three across controllers of comparable nominal fidelity and contain structure-dependent information not captured by nominal differential sensitivity alone.

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