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上海交通大学自然科学研究院最新成果:物质在引力塌缩的过程中根据它的构成物质辐射出不等量的辐射

近期,上海交通大学自然科学研究院及物理与天文系戴德昌和美国纽约州立大学布法罗分校Dejan Stojkovic 共同在Physics Letters B发表了题为 Collapsing objects with the same gravitational trajectory can radiate away different amount of energy的文章。

本论文研究引力塌缩所发射的辐射和其组成成分的相依性.物质在引力的作用下会沿着测地线方向前进. 但是对于一个带电粒子而言, 除了引力场造成加速度外,带电粒子同时还辐射出能量.这些辐射强度跟物质的组成相关,因此可以用来确认引力塌缩物质的组成.但是宇宙中很少有独立的带电物质存在.对于不带电的物质团在塌缩的过程中是否会根据它的组成发射出不一样的辐射仍是未确定的问题. 例如一般的物质及暗物质都属于电荷平衡状态,它们在引力的作用下是否发射出不一样的辐射便是本文章想讨论的重点.虽然暗物质的物理特性还没被完全研究清楚, 但是暗物质的作用力远小于一般物质.不和其它物质作用的物质在物理上便是透明的物质.本论文通过比较透明的壳层和不透明(全反射)的壳层在引力作用下的辐射差异并藉此类比暗物质和一般物质的辐射情况.研究结果表明电中性的物质在引力塌缩的过程中会根据它的组成辐射出能量,因此仍可以用来重构物质的分布。

参考文献: De-Chang Daia and Dejan Stojkovicb, “Collapsing objects with the same gravitational trajectory can radiate away different amount of energy”

We study radiation emitted during the gravitational collapse from two different types of shells. We assume that one shell is made of dark matter and is completely transparent to the test scalar (for simplicity) field which belongs to the standard model, while the other shell is made of the standard model particles and is totally reflecting to the scalar field. These two shells have exactly the same mass, charge and angular momentum (though we set the charge and angular momentum to zero), and therefore follow the same geodesic trajectory. However, we demonstrate that they radiate away different amount of energy during the collapse. This difference can in principle be used by an asymptotic observer to reconstruct the physical properties of the initial collapsing object other than mass, charge and angular momentum. This result has implications for the information paradox and expands the list of the type of information which can be released from a collapsing object.