Gravity as the breakdown of conformal invariance

Understand

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.