Gravitationally bound Bose condensates with rotation

Abstract

We develop a self-consistent, Gravitoelectromagnetic (GEM) formulation of a slowly rotating, self-gravitating and dilute Bose-Einstein condensate (BEC), intended for astrophysical applications in the context of dark matter halos. GEM self-consistently incorporates the effects of frame dragging to lowest order in v/c via the Gravitomagnetic field. BEC dark matter has attracted attention as an alternative to Cold dark matter (CDM) and Warm dark matter (WDM) for some time now. The BEC is described by the Gross-Pitaevskii-Poisson (GPP) equation with an arbitrary potential allowing for either attractive or repulsive interactions. Owing to the difficulty in obtaining exact solutions to the GEM equations of motion without drastic approximations, we employ the variational method to examine the conditions under which rotating condensates, stable against gravitational collapse, may form in models with attractive and repulsive quartic interactions. We also describe the approximate dynamics of an imploding and rotating condensate by employing a collective coordinate description in terms of the condensate radius. *

Global view of QCD axion stars

“…A recent surge in studies of boson stars [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] stems, in part, from the renewed interest in determining whether dark matter (DM) could consist of condensates of ax-ions or other axion like particles. A particularly wellmotivated scalar DM candidate is the QCD axion, parametrized by a decay constant f = 6 × 10 11 GeV and particle mass m = 10 −5 eV; 2 as a result, bound states of QCD axions (which we will call QCD axion stars) have received special attention.…”

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“…Axion stars were considered first around 30 years ago, originally suggested to form from collapse of overdense miniclusters in the early universe [10,11] (see also more recent simulations [12]). Since then, many properties of axion stars have been studied extensively; these include structural stability [13][14][15][16][17][18][19][20][21][22] (including nonzero angular momentum [23][24][25]), the process of gravitational collapse [26][27][28][29][30][31][32], and their decay through emission of relativistic particles [33][34][35][36][37][38]. There has recently been a significant amount of work regarding relativistic corrections more generally to the classical field description of axion stars [39][40][41][42].…”

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