Dark energy and dimensional transmutation in R2 gravity

Saturday, 20 June, 2015

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Recent work has shown that non-local modifications of gravity involving terms such as m2R□−2R (and no cosmological constant) provide a phenomenologically viable alternative to ΛCDM. We discuss the possibility that such non-local terms emerge in the far infrared from the running of the coupling constant associated to the R2 term in higher-derivative gravity, which is asymptotically free in the ultraviolet and strongly coupled in the infrared. In this scenario the mass scale m of the non-local model emerges from dimensional transmutation, similarly to ΛQCD for strong interactions, leading to a technically natural value of the scale associated to dark energy. We also argue that the emergence of the non-local term can be understood as a dynamical mass generation for the conformal mode, as a response of the vacuum to the strong infrared fluctuations that are generated by the anomaly-induced effective action.


Michele Maggiore