The Mad Era: A Possible New Resolution to the Horizon, Flatness, and Monopole Problems
Abstract
A cosmology with a dynamical Planck mass mpl is shown to solve the horizon and monopole problems (and possibly flatness) if there is an early MAD (modified aging) era where the universe becomes older than in the standard model as a result of a large mpl: the causality condition is mpl(Tc)/ mpl(To) Tc/To (Tc is some high temperature while To = 2.74K.) Unlike inflation, there is no period of vacuum domination nor any entropy violation. We study: a) bare scalar theories of gravity, b) self-interacting models, and c) bare theories with a phase transition in the matter sector.
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