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arXiv · 2608.24732

Certified Fidelity Susceptibility from Classical Shadows

Kiran Adhikari
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Abstract

Fidelity susceptibility is a useful probe of quantum phase transitions and quantum metrology, but its direct evaluation on a quantum device is challenging. By integrating Krylov-subspace methods with a resolvent-based reformulation, we present a method for certifying fidelity susceptibility using randomized single-copy measurements across repeated ground-state preparations. The resulting approximations form monotone lower bounds to the exact fidelity susceptibility and converge geometrically. We also present applications to metrology and linear static susceptibilities.

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Kiran Adhikari. 2026-08-25. Certified Fidelity Susceptibility from Classical Shadows. https://arxiv.org/abs/2608.24732

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