Abstract Details
| Name: Sanjay Shukla Affiliation: Indian Institute of Science Conference ID: ASI2024_377 Title : Gravity- and temperature-driven phase transitions in a model for collapsed axionic condensates Authors and Co-Authors : Sanjay Shukla, Akhilesh Kumar Verma, Marc E. Brachet, Rahul Pandit Abstract Type : Poster Abstract Category : Galaxies and Cosmology Abstract : We study the evolution and rotational dynamics of axion condensates in the cubic-quintic Gross-Pitaevskii-Poisson equation (cq-GPPE), which we use to model axions in dark-matter haloes or in axion stars, for both zero and finite temperature T . At T = 0, we use a Gaussian Ansatz for a spherically symmetric density to obtain parameter regimes in which we might expect to find compact axionic condensates. We show that, as gravitational strength increases, the equilibrium configuration goes from a tenuous axionic gas, to flat sheets or Zeldovich pancakes, cylindrical structures, and finally a spherical axionic condensate. The transitions between these states yield thermally driven first-order phase transitions and their associated hysteresis loops. Finally, we discuss how our cq-GPPE approach can be used to follow the spatiotemporal evolution of a rotating axion condensate and also a rotating binary-axion-condensate system; in particular, we demonstrate, in the former, the emergence of vortices at large angular speeds Ω and, in the latter, the rich dynamics of the mergers of the components of this binary system, which can yield vortices in the process of merging. |