F\rangle $ is an average that includes a little bit of “future”. ]]>

\sqrt{-g}R_{\mu \nu }R^{\mu \nu }$ and $\sqrt{-g}R^{2}$. In this paper, we compute the one-loop renormalization of the theory and the absorptive part of the graviton self energy. The results illustrate the mechanism that makes renormalizability compatible with unitarity. The fakeons disentangle the real part of the self energy from the imaginary part. The former obeys a renormalizable power counting, while the latter obeys the nonrenormalizable power counting of the low energy expansion and is consistent with unitarity in the limit of vanishing cosmological constant. The value of the absorptive part is related to the central charge $c$ of the matter fields coupled to gravity.

→ Mathematica files attached to paper

J. High Energ. Phys. 05 (2018) 27 | DOI: 10.1007/JHEP05(2018)027

]]>J. High Energy Phys. 02 (2018) 141 | DOI: 10.1007/JHEP02(2018)141

]]>→ Mathematica files attached to paper

J. High Energy Phys. 06 (2017) 086 | DOI: doi:10.1007/JHEP06(2017)086

]]>Phys. Rev. D 96 (2017) 045009 | DOI: 10.1103/PhysRevD.96.045009

]]>J. High Energy Phys. 06 (2017) 066 | DOI: 10.1007/JHEP06(2017)066

]]>However, in **a recent paper** it was shown that the two formulations are not always equivalent. In particular, they are not equivalent in a wide realm of quantum field theories that is **relevant for the search of quantum gravity**.

The two formulations differ so much that one of the two, the Minkowski one, is **mathematically inconsistent**, because it leads to nonlocal divergences that cannot be subtracted away. The only viable formulation of quantum field theory is thus the Wick rotation of a Euclidean theory.

This observation could have very broad consequences. Ultimately, it tells us that the environment of quantum field theory is not Minkowski spacetime, but a different kind of spacetime, which we may call * Wick spacetime*, that is to say the Wick rotated Euclidean space.

If we believe that **quantum field theory is the correct framework to describe nature**, as all experimental evidence suggests so far, the conclusion extends from quantum field theory to nature itself, i.e.

the universe does not live in Minkowski spacetime, but in Wick spacetime.

Said differently,

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time is not time, but an imaginary space.

Ann. Phys. 394 (2018) 294 | DOI: 10.1016/j.aop.2018.04.034

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