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A New Perspective on Cosmic Coincidence Problems

Nima Arkani-Hamed·Lawrence J. Hall·Christopher Kolda·Hitoshi Murayama
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Abstract

Cosmological data suggest that we live in an interesting period in the history of the universe when ρ_Λ\sim ρ_M \sim ρ_R. The occurence of any epoch with such a "triple coincidence" is puzzling, while the question of why we happen to live during this special epoch is the "Why now?" problem. We introduce a framework which makes the triple coincidence inevitable; furthermore, the ``Why now?'' problem is transformed and greatly ameliorated. The framework assumes that the only relevant mass scales are the electroweak scale, M_{EW}, and the Planck scale, M_{Pl}, and requires ρ_Λ^{1/4} \sim M_{EW}^2/M_{Pl} parametrically. Assuming that the true vacuum energy vanishes, we present a simple model where a false vacuum energy yields a cosmological constant of this form.

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Nima Arkani-Hamed, Lawrence J. Hall, Christopher Kolda, Hitoshi Murayama. 2000-06-01. A New Perspective on Cosmic Coincidence Problems. https://doi.org/10.1103/physrevlett.85.4434

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