Collider and Cosmological Signatures of the Electroweak Phase Transition

In this talk, I will discuss strategies for testing the nature of the electroweak phase transition in extensions of the Standard Model. I will first focus on gravitational wave signatures of strong first order transitions and show that the proposed space-based interferometer LISA can have a realistic chance of observing such a signal arising in many well-motivated scenarios beyond the Standard Model. The latter portion of the talk will concentrate on collider signatures of the electroweak phase transition in singlet scalar extensions of the Standard Model Higgs sector. In these scenarios, a strong first order electroweak phase transition is generally correlated with the cross-section for double scalar production at colliders. I will discuss the prospects for observing these processes at future colliders.