Acceleration of the Universe, String Theory and a Varying Speed of Light

Source: arXiv


The existence of future horizons in spacetime geometries poses serious problems for string theory and quantum field theories. The observation that the expansion of the universe is accelerating has recently been shown to lead to a crisis for the mathematical formalism of string and M-theories, since the existence of a future horizon for an eternally accelerating universe does not allow the formulation of physical S-matrix observables. Postulating that the speed of light varies in an expanding universe in the future as well as in the past can eliminate future horizons, allowing for a consistent definition of S-matrix observables.

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Available from: John Moffat, Jul 15, 2014
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    • "Accurate measurement of the speed of propagation of gravitational waves can constrain extra-dimensional " brane-world " theories in which gravity propagates in the bulk of extra dimensions [8] [9] [10] [11] [12] [13] [14], while the particles of the Standard Model are confined to a 3+1 dimensional subspace known as a brane. It has been argued that in many cases Poincaré invariance should be violated in the bulk [15] [16] [17] [18] [19] [20] [21] giving rise to an anomalous dispersion relation for gravitational waves. 2 No Lorentz violation would show up in the standard model, provided our brane is Poincaré invariant. "
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