Dr Nils Siemonsen (Princeton University) gives a webinar on ‘Vortex dynamics in strong gravitational fields’ (4PM UK time)

Chair: Samuli Autti

Vortices play a fundamental role in diverse physical systems, from condensed matter to astrophysics and cosmology. Light scalar extensions to the Standard Model may be relevant in the early universe and to explain dark matter. In both contexts, the appearance of vortices in the form of, for instance, rotating solitons or global cosmic strings leads to a rich phenomenology with possibly observable consequences. In this talk, I will explore vortex formation and evolution in these two settings, where gravitational fields are relativistic. First, I will discuss vortex formation in the mergers of self-gravitating relativistic solitons called boson stars. Using numerical simulations, I will show how angular momentum redistribution and vortex evolution during the coalescence leads to intricate merger dynamics, as well as present the associated gravitational wave emissions [1,2]. Second, and turning to vortex dynamics in the early universe, I will show that the production of a network of global strings can ensue driven by a parametric resonance around initially spatially uniform field configurations. The entire network forms and annihilates periodically in large regions of parameter space [3]. I will discuss the late-time evolution of this system and aspects of the emitted gravitational wave spectrum. These results highlight the intricacies of vortex evolution in strongly curved spacetimes and their relevance across multiple scales in fundamental physics.

[1] N. Siemonsen and W. E. East, Phys.Rev.D 108 (2023) 12, 124015

[2] N. Siemonsen and W. E. East, Phys.Rev.D 107 (2023) 12, 124018

[3] M. Fedderke, J. Huang, N. Siemonsen, (in prep)