Escher in the Sky

الأصل · EN

The cosmological models called α-attractors provide an excellent fit to the latest observational data. Their predictions nₛ = 1-2/N and r = 12α/N² are very robust with respect to the modifications of the inflaton potential. An intriguing interpretation of α-attractors is based on a geometric moduli space with a boundary: a Poincare disk model of a hyperbolic geometry with the radius √3α, beautifully represented by the Escher's picture Circle Limit IV. In such models, the amplitude of the gravitational waves is proportional to the square of the radius of the Poincare disk.