Robert Mann
U Waterloo
I will sketch out two possible alternatives to the standard inflationary scenario.
One, called M-flation, is a string-motivated model with three scalar field matrices and gauge fields in the adjoint representation of the U(N) gauge group, one of which appears as the effective inflaton while the rest play the role of isocurvature fields during inflation and preheat fields afterwards. The power spectra of gravitational waves produced during the preheating stage following M-flation can be computed, The preliminary numerical and peaks in the GHz band with an amplitude Ωgwh2∝10−16, suggesting that the model has concrete predictions for the ultra-high frequency gravity-wave probes.
The other is a more exotic idea, in which the big bang is hidden behind a causal horizon. This model is in the context of a DGP braneworld description of cosmology with both 4d induced and 5d bulk gravity. The universe emerges as a spherical 3-brane out of the formation of a 5d Schwarzschild black hole.
419B LGRT
