When: Wednesday, October 18, 2023, 7:30 PM - 9:00 PMWhere: Physics (G. O. Jones building) Room 516, Mile End
Speaker: Joe Jackson (ICG)
The separate universe approach gives an intuitive and accurate way to describe cosmological perturbations during inflation. This is done by perturbing the local universe and following the subsequent evolution. On large enough scales the homogeneous equations of motion can be used. But if inflaton rapidly changes behaviour, such as during a slow-roll to ultra-slow-roll transition, these homogeneous components can be mixed with non-homogeneous components. This can change the evolution of even large scale super-horizon modes. This behaviour has implications for the separate universe approach, stochastic inflation and primordial black hole production.