Search Talks

A stochastic gravitational wave background (GWB) produced in the early universe would necessarily exhibit anisotropies analogous to the CMB. In multi-field inflationary scenarios, anisotropies in GWB could differ significantly from those of the CMB if sourced by a quantum field different from the one sourcing CMB. In these scenarios, however, the more interesting case of highly anisotropic GWB typically comes at the cost of suppressed isotropic GWB signal. In this talk, I will present models of modified post-inflationary cosmology in which this tradeoff is made less severe. Such models significantly improve the detection prospects of these highly anisotropic GWBs at future GW experiments.

In these lectures, I discuss how GWs are produced by cosmological phase transitions. We start by a short recap of gravitational waves and then move to early attempts using pairs of bubbles and the envelope approximation. Next we cover the energy budget of phase transitions and the impact of sound waves. Finally I comment on recent developments.
 

This session will be mostly practical. Within the framework of the 2-species LV model, we will use nullcline analysis to predict the outcome of competition in different situations. These include cases in which either or both competitors are subject to cooperative growth, which can lead to alternative stable states that emerge in (2-species) co-culture, but that are absent in any of the (1-species) monocultures.