Sensing relativistic quantum fields with minimally perturbing local measurements

• URL: http://arxiv.org/abs/2607.17920v1
• Date: Mon, 20 Jul 2026 13:16:36 GMT
• Title: Sensing relativistic quantum fields with minimally perturbing local measurements
• Abstract summary: We develop a framework for minimally perturbing local measurements in relativistic quantum field theory.<n>Field properties are sensed by weakly coupled pointers and encapsulated in conditional expectation values dependent on a postselection of the field state.<n>We illustrate our approach with three applications: a spacelikeness detector for causal-structure sensing, counting particle-creation densities in a supercritical potential and non-destructive discrimination between entangled states of the field and mixtures.
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• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: We develop a framework for minimally perturbing local measurements in relativistic quantum field theory, with the aim to sense local properties of the field in a non-destructive manner. The field properties are sensed by weakly coupled pointers and encapsulated in conditional expectation values dependent on a postselection of the field state. Our operational protocol uses causally admissible Kraus updates for the field, in line with recent relativistic measurement theories, keeping in mind restrictions related to ``impossible measurements''. We illustrate our approach with three applications: a spacelikeness detector for causal-structure sensing, counting particle-creation densities in a supercritical potential and non-destructive discrimination between entangled states of the field and mixtures.

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