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[[UTAPwiki/セミナー/初期宇宙・相対論速報]] *Title: Cosmology and the AB transition in superfluid helium 3 [#x7d9521e] **Speaker: Mark Hindmarsh [#uba40e74] TBA The extreme purity and precise control of pressure and temperature achievable in the laboratory make the superfluid Helium-3 AB transition ideal for testing the theory of first order phase transitions in the early Universe. Such a phase transition, which appears naturally in many extensions of the Standard Model of particle physics, could provide the departure from equilibrium needed for a dynamical explanation of the baryon asymmetry of the Universe. It could also produce gravitational waves of a frequency observable by future space-based detectors such as the Laser Interferometer Space Antenna (LISA). All calculations of the gravitational wave power spectrum rely on a relativistic version of the classical nucleation theory, due to Coleman and Linde. Yet when the A phase of superfluid He-3 is supercooled, the B phase appears far faster than classical nucleation theory would predict. If the appearance of B phase is due to a new rapid intrinsic mechanism, gravitational wave production could be rendered negligible. I discuss how the nucleation rate influences gravitational wave production at a first order phase transition in the early Universe, and make quantitive analogies with the AB transition. I outline future experiments designed to eliminate extrinsic nucleation mechanisms, and how they can be used to test cosmological nucleation theory. |