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  • Open Access

Causal measurement in quantum field theory: Spacetime

Robert Oeckl*

  • *Contact author: robert@matmor.unam.mx
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Phys. Rev. D 113, 085002 – Published 2 April, 2026

DOI: https://doi.org/10.1103/5gl8-3j6p

Abstract

We provide a framework and explicit construction for the regularized measurement of a large class of spacetime-localized observables in bosonic quantum field theory. The measurements fully satisfy relativistic causality and causal transparency, i.e., avoid unphysical superluminal signaling. We show explicitly how the measurement of time-extended observables backreacts on itself and induces correlations between other measurements in its causal future. Our framework is fully compositional in spacetime and extends previous results on the measurement of instantaneous observables.

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Phys. Rev. D 113, 085002– Published 2 April, 2026
  • Received 18 November 2025
  • Accepted 16 March 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

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