Non-perturbative unitarity and fictitious ghosts in quantum gravity
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We discuss aspects of non-perturbative unitarity in quantum field theory. The additional ghost degrees of freedom arising in “truncations” of an effective action at a finite order in derivatives could be fictitious degrees of freedom. Their contributions to the fully-dressed propagator – the residues of the corresponding ghost-like poles – vanish once all operators compatible with the symmetry of the theory are included in the effective action. These “fake ghosts” do not indicate a violation of unitarity.
Original language | English |
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Article number | 135911 |
Journal | Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics |
Volume | 811 |
ISSN | 0370-2693 |
DOIs | |
Publication status | Published - 10 Dec 2020 |
Bibliographical note
Funding Information:
The authors thank D. Anselmi, J. Donoghue and A. Eichhorn for insightful discussions, and A. Eichhorn for initial inputs on the development of this work. The research of AP is supported by the Alexander von Humboldt Foundation .
Publisher Copyright:
© 2020 The Author(s)
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