Quantum gravity, fakeons and microcausality
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We investigate the properties of fakeons in quantum gravity at one loop. The theory is described by a graviton multiplet, which contains the fluctuation hμν of the metric, a massive scalar ϕ and the spin-2 fakeon χμν . The fields ϕ and χμν are introduced explicitly at the level of the Lagrangian by means of standard procedures. We consider two options, where ϕ is quantized as a physical particle or a fakeon, and compute the absorptive part of the self-energy of the graviton multiplet. The width of χμν , which is negative, shows that the theory predicts the violation of causality at energies larger than the fakeon mass. We address this issue and compare the results with those of the Stelle theory, where χμν is a ghost instead of a fakeon.
KeywordsBeyond Standard Model Models of Quantum Gravity Renormalization Regularization and Renormalons
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- T.D. Lee and G.C. Wick, Negative Metric and the Unitarity of the S Matrix, Nucl. Phys. B 9 (1969) 209 [INSPIRE].
- T.D. Lee and G.C. Wick, Finite Theory of Quantum Electrodynamics, Phys. Rev. D 2 (1970) 1033 [INSPIRE].
- R.E. Cutkosky, P.V. Landshoff, D.I. Olive and J.C. Polkinghorne, A non-analytic S matrix, Nucl. Phys. B 12 (1969) 281 [INSPIRE].
- J. Julve and M. Tonin, Quantum Gravity with Higher Derivative Terms, Nuovo Cim. B 46 (1978) 137 [INSPIRE].
- E.S. Fradkin and A.A. Tseytlin, Renormalizable asymptotically free quantum theory of gravity, Nucl. Phys. B 201 (1982) 469 [INSPIRE].
- I.G. Avramidi and A.O. Barvinsky, Asymptotic freedom in higher derivative quantum gravity, Phys. Lett. B 159 (1985) 269 [INSPIRE].
- S. Coleman, Acausality, in Erice 1969 Ettore Majorana School On Subnuclear Phenomena, Academic Press, New York (1970).Google Scholar
- K.S. Stelle, Renormalization of Higher Derivative Quantum Gravity, Phys. Rev. D 16 (1977) 953 [INSPIRE].
- W.L. van Neerven, Dimensional Regularization of Mass and Infrared Singularities in Two Loop On-shell Vertex Functions, Nucl. Phys. B 268 (1986) 453 [INSPIRE].
- M. Consoli, W.F.L. Hollik and F. Jegerlehner, Electroweak radiative corrections for Z physics, in Z physics at LEP 1, Vol. 1: Standard physics, G. Altarelli, R. Kleiss and C. Verzegnassi eds., CERN-1989-008-V-1.Google Scholar
- R.J. Eden, P.V. Landshoff, D.I. Olive and J.C. Polkinghorne, The Analytic S-Matrix, Cambridge University Press, Cambridge, U.K. (1966) [INSPIRE].