2007/07/31 by Zvi Bern, Z. Bern, J. J. Carrasco +5 · 1 citation
Physics and Astronomy · #Action (physics) #Amplitude #Asymptotic safety in quantum gravity #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Einstein #Mathematical physics #Noncommutative and Quantum Gravity Theories #Perturbation theory (quantum mechanics) #Physics #Quantum #Quantum gravity #Quantum mechanics #Supergravity #Supersymmetry #Theoretical physics #Ultraviolet #Unitarity #hep-th
paper · pdf · doi:10.1103/physrevd.77.025010
published as Phys.Rev.D77:025010,2008 · 40 pages, 6 figures. v2 minor corrections, removed comment on absence of rational terms in N=4 supergravity
openalex publication_date 2008/01/11 · arxiv created 2011/01/30 · arxiv updated 2015/03/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Recent computations of scattering amplitudes show that N=8 supergravity is surprisingly well behaved in the ultraviolet and may even be ultraviolet finite in perturbation theory. The novel cancellations necessary for ultraviolet finiteness first appear at one loop in the guise of the ``no-triangle hypothesis.'' We study one-loop amplitudes in pure Einstein gravity and point out the existence of cancellations similar to those found previously in N=8 supergravity. These cancellations go beyond those found in the one-loop effective action. Using unitarity, this suggests that generic theories of quantum gravity based on the Einstein-Hilbert action may be better behaved in the ultraviolet at higher loops than suggested by naive power counting, though without additional (supersymmetric) cancellations they diverge. We comment on future studies that should be performed to support this proposal.