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  • Open Access

Worldline instantons for nonperturbative particle production by space and time dependent gravitational fields

Philip Semrén* and Greger Torgrimsson†

  • *Contact author: philip.semren@umu.se
  • †Contact author: greger.torgrimsson@umu.se
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Phys. Rev. D 113, 056005 – Published 4 March, 2026

DOI: https://doi.org/10.1103/lpwp-y3g4

Abstract

We develop a worldline-instanton approach for calculating the momentum spectrum of particles produced by gravitational fields that depend on both space and time. The instantons are open. The middle part is complex and describes the formation region, while the ends describe the trajectories of asymptotic particles.

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Phys. Rev. D 113, 056005– Published 4 March, 2026
  • Received 22 August 2025
  • Accepted 12 February 2026
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