Physically implementable local QFT measurements
Given a local algebraic instrument and a compact spacetime coupling region, characterize whether localized coupling to an admissibly prepared probe field can implement or approximate the instrument while respecting causality and preserving the chosen admissibl
Problem statement
Given a local algebraic instrument and a compact spacetime coupling region, characterize whether localized coupling to an admissibly prepared probe field can implement or approximate the instrument while respecting causality and preserving the chosen admissible state class.
Lean 4
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Background
An abstract observable or completely positive instrument need not come with a causal laboratory implementation. In relativistic QFT, a measurement model must specify the probe, its preparation, the spacetime support of the coupling, and the final accessible readout; naive ideal measurements of extended observables can conflict with causal requirements.
Published baseline: Mandrysch–Navascués (2025) construct Gaussian-modulated measurements of smeared fields within the Fewster–Verch probe framework and establish a movable measurement cut for that class. Thus neither all local field measurements nor the basic probe formalism are missing.
The open reachability question is which more general instruments admit such a realization or controlled approximation. Fix the field model, state class, localization and error criterion; quantify the necessary probe energy and coupling cost, and identify impossibility criteria. Interacting and gauge-constrained models require their own assumptions. This operational task is distinct from outcome ontology (F1) and from computing continuum entanglement (QF8).
Progress & source assessment
Source catalogue review: 4 September 2026. Improved indicates partial progress, including qualified preprint claims.
published: Gaussian-modulated smeared-field measurements and a movable probe cut are constructed; arbitrary instrument reachability is not established. Evidence
- [1]Mandrysch & Navascués, 'Quantum Field Measurements in the Fewster-Verch Framework', Letters in Mathematical Physics 115, 115 (2025) link
Recorded progress
Add yours →Nothing recorded yet. A pointer to a paper the entry is missing counts.
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