# Purely virtual particles versus Lee-Wick ghosts: Physical Pauli-Villars fields, finite QED, and quantum gravity

@article{Anselmi2022PurelyVP, title={Purely virtual particles versus Lee-Wick ghosts: Physical Pauli-Villars fields, finite QED, and quantum gravity}, author={Damiano Anselmi}, journal={Physical Review D}, year={2022} }

We reconsider the Lee-Wick (LW) models and compare their properties to the properties of the models that contain purely virtual particles. We argue against the LW premise that unstable particles can be removed from the sets of incoming and outgoing states in scattering processes. The removal leads to a non-Hermitian classical limit, besides clashing with the observation of the muon. If, on the other hand, all the states are included, the LW models have a Hamiltonian unbounded from below or…

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