HEP Theory Seminar
Abstract: Even if dramatic cosmological events or large dark-sector objects have no direct couplings to Standard Model particles, they can still leave observable signatures through their gravitational effects.
In this talk, I will discuss cosmological perturbations from several types of extended objects, including first-order phase-transition bubbles, domain walls and ultralight dark matter. I will highlight their common features, as well as distinctive signatures such as enhanced large-scale perturbations from domain walls and non-Gaussianity from ultralight dark matter. I will conclude with current constraints and future prospects for probing these gigantic but elusive objects.