The particle that makes up the dark matter of the Universe could be an axion or axionlike particle. A collection of axions can condense into a bound Bose-Einstein condensate called an axion star. It is possible that a significant fraction of the axion dark matter is in the form of axion stars. This would make some efforts to identify the axion as the dark matter particle more challenging, but it would also open up new possibilities. The basic properties of axion stars, which can be gravitationally bound or bound by self-interactions, are summarized. Axions are naturally described by a relativistic field theory with a real scalar field, but low-energy axions can be described more simply by a classical nonrelativistic effective field theory with a complex scalar field.

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座谈会：轴突星的物理学

组成宇宙暗物质的粒子可以是轴或类轴粒子。一系列的轴可凝结成束缚的玻色-爱因斯坦凝聚物，称为轴之星。轴突暗物质的很大一部分可能是轴突星的形式。这将使识别轴突成为暗物质粒子更具挑战性，但也将开辟新的可能性。总结了轴力恒星的基本特性，可以通过重力作用或通过自身相互作用来约束。相对轴力场自然是由具有相对标量场的相对论场论来描述的，但是低能轴距可以由具有复杂标量场的经典非相对论有效场论来更简单地描述。