RevModPhys.84.671

Resonance massive graviton can also be generalized

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Unformatted text preview: olution to the problem of quantum corrections to the cosmological constant. It is a remarkable fact that the Ã3 theories of Sec. VIII exist and are ghost free, and that they are found simply by tuning some coefficients in the generic graviton potential. There are many interesting outstanding issues. One is the nature of the Ã3 theory. Is there a symmetry or a topological construction that explains the tunings of the coefficients necessary to achieve the Ã3 cutoff? Is there some construction free of prior geometry that would contain this theory? Is there an extra-dimensional construction? There are also many questions related to the quantum properties of these theories. Apart from the order of magnitude estimates presented in this review and a few sporadic calculations, the detailed quantum properties of this theory and others remain relatively unexplored. The same goes for nonperturbative quantum properties, such as how a massive graviton would modify black hole thermodynamics, Hawking radiation, or holography (Babak and Grishchuk, 2003; Aharony, Clark, and Karch, 2006; Katz, Lewandowski, and Schwartz, 2006; Kiritsis, 2006; Kiritsis and Niarchos, 2009; Niarchos, 2009; Capela and Tinyakov, 2011). The cutoff Ã3 is still rather low, however, so at best this theory in its current perturbative expansion can provide only a partial solution to the cosmological constant naturalness problem. Finding more natural constructions of these theories would go a long way toward solving the major issue, which is that of UV completion; is it possible to find a standard UV completion for a massive graviton, analogous to what the Higgs mechanism provides for a massive vector? Or is there some incontrovertible obstruction that forces any UV Kurt Hinterbichler: Theoretical aspects of massive gravity completion to violate Lorentz invariance, locality, or some other cherished property? If so, there may be a nonstandard UV completion, or it could be that massive gravity really is inconsistent, in the sense that there really is no way whatsoever to UV complete it. There has been work on holography of massive gravitons in anti–de Sitter/conformal field theory (AdS/CFT) (Aharony, Clark, and Karch, 2006; Kiritsis, 2006; Kiritsis and Niarchos, 2009; Niarchos, 2009), which provides a UV completion for theories in AdS space containing massive gravity. Even a partial UV completion, one that raises the cutoff to MP , would be extremely important, as this is all that is required to offer a solution to the cosmological constant naturalness problem. One possibility is that the scale Ã3 , while indicating a breakdown in perturbation theory, does not signal the activation of any new degrees of freedom, so that the theory is already self-complete up to MP . Since there are multiple parameters in the theory, it is likely that there is some other expansion, such as a small m expansion, which reorganizes the perturbation theory into one which yields perturbative access to scales abov...
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This document was uploaded on 09/28/2013.

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