Particle decay in expanding Friedmann-Robertson-Walker universes

@article{Lankinen2018ParticleDI,
  title={Particle decay in expanding Friedmann-Robertson-Walker universes},
  author={Juho Lankinen and Iiro Vilja},
  journal={Physical Review D},
  year={2018},
  volume={98}
}
The lack of energy conservation introduces new particle processes in curved spacetime that are forbidden in flat space. Therefore one has to be very cautious about using the results calculated in Minkowskian space in early universe applications. This is true for particle decay rates in particular, which need to be calculated using quantum field theory in curved spacetime. Previous studies are usually restricted to using minimal or conformal coupling for the decaying particle, while using a more… 

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