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arXiv · 1505.04649

Gravity as the breakdown of conformal invariance

Giovanni Amelino-Camelia·Michele Arzano·Giulia Gubitosi·Joao Magueijo
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Abstract

We propose that at the beginning of the universe gravity existed in a limbo either because it was switched off or because it was only conformally coupled to all particles. This picture can be reverse-engineered from the requirement that the cosmological perturbations be (nearly) scale-invariant without the need for inflation. It also finds support in recent results in quantum gravity suggesting that spacetime becomes two-dimensional at super-Planckian energies. We advocate a novel top-down approach to cosmology based on the idea that gravity and the Big Bang Universe are relics from the mechanism responsible for breaking the fundamental conformal invariance. Such a mechanism should leave clear signatures in departures from scale-invariance in the primordial power spectrum and the level of gravity waves generated.

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Giovanni Amelino-Camelia, Michele Arzano, Giulia Gubitosi, Joao Magueijo. 2015-05-18. Gravity as the breakdown of conformal invariance. https://doi.org/10.1142/s0218271815430026

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