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arXiv · 2505.02840

Time-Ordering in the Dyson-Unruh Problem: Accelerated Observers and Quantum Fields

Arash Azizi
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Abstract

We investigate the structure of time-ordered perturbative expansions in quantum field theory (QFT) in curved spacetime, focusing on the interaction between a scalar field and multiple Unruh-DeWitt detectors undergoing uniform acceleration. Assuming the existence of a timelike Killing vector field, which serves as a global time coordinate, we express each detector's proper time in terms of this global time and consistently implement time-ordering in the Dyson series. Using light-cone coordinates and detector worldlines, we construct all possible interaction terms for two detectors at first, second, and third orders in perturbation theory. Our formalism enables a systematic classification of contributions to the S-matrix, resolving ordering ambiguities that arise due to differing accelerations and causal structure.

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Arash Azizi. 2025-04-18. Time-Ordering in the Dyson-Unruh Problem: Accelerated Observers and Quantum Fields. https://arxiv.org/abs/2505.02840

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