Residual Fisher Information in Measurement-Error Uncertainty

Abstract:Measurement error in the Watanabe-Sagawa-Ueda formulation is the excess estimation error of a classical record over the quantum statistical limit. We show that, at the quantum-instrument level, this excess has an exact decomposition. The record-only error matrix equals a residual-aware error matrix plus a positive Schur-complement term fixed by Fisher information left in the unread post-measurement system. Thus measurement error separates into intrinsic instrument loss and record-restriction loss

arXiv:2609.31311 [quant-ph]

(or arXiv:2609.31311v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2609.31311 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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