We study the Bose condensation of scalar dark matter in the presence of both gravitational and self-interactions. Axions and other scalar dark matter in gravitationally bound miniclusters or dark matter halos are expected to condense into Bose-Einstein condensates called Bose stars. This process has been shown to occur through attractive self-interactions of the axion-like particles or through the field’s self gravitation. We show that in the high-occupancy regime of scalar dark matter, the Boltzmann collision integral does not describe either gravitational or self-interactions, and derive kinetic equations valid for these interactions. We use this formalism to compute relaxation times for the Bose-Einstein condensation, and find that condensation into Bose stars could occur within the lifetime of the universe. The self-interactions reduce the condensation time only when they are very strong.

中文翻译：

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轴突小簇中玻色-爱因斯坦凝聚的弛豫时间

我们研究了重力和自相互作用同时存在下标量暗物质的玻色凝聚。引力束缚的小团簇或暗物质光环中的轴子和其他标量暗物质有望凝结为玻色-爱因斯坦凝聚物，称为玻色星。已经表明该过程是通过轴突状颗粒的有吸引力的自相互作用或通过场的自重而发生的。我们表明，在标量暗物质的高占有率体制中，玻尔兹曼碰撞积分没有描述引力或自相互作用，并得出了对这些相互作用有效的动力学方程。我们使用这种形式主义来计算玻色-爱因斯坦凝聚的弛豫时间，并发现凝聚成玻色恒星的过程可能发生在宇宙的生命周期内。