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上海交通大学自然科学研究院最新成果:前霍金辐射可以重构引力塌缩物质的质量分布

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 Pre-Hawking radiation may allow for reconstruction of the mass distribution of the collapsing object的文章。

黑洞是引力塌缩的最后产物.在黑洞形成后,它会根据自身的质量,电荷和角动量产生霍金辐射.霍金辐射跟黑洞形成的历史无关,因此霍金提出黑洞信息丢失问题.信息丢失问题困扰着许多黑洞物理学家.霍金本人也相继提出许多解释方法.其中一个解释方法是具有相同物理参数的黑洞可以伴随许多不一样的真空态.这些真空态可以解释信息丢失的问题.将黑洞当作引力演化的终态并藉此研究黑洞形成前的历史显然无法解决信息丢失问题,因此我们提出必须考虑黑洞形成过程中的前霍金辐射.前霍金辐射跟物质塌缩的历史有关,所以可以用来重构形成黑洞的历史.我们研究在不一样的初始条件下塌缩的物质所发出的辐射.研究结果显示前霍金辐射确实跟演化历史相关.本研究证明有部分的黑洞形成历史可由前霍金辐射重构。

参考文献: De-Chang Daia and Dejan Stojkovicb, “Pre-Hawking radiation may allow for reconstruction of the mass distribution of the collapsing object”

Hawking radiation explicitly depends only on the black hole’s total mass, charge and angular momentum. It is therefore generally believed that one cannot reconstruct the information about the initial mass distribution of an object that made the black hole. However, instead of looking at radiation from a static black hole, we can study the whole time-dependent process of the gravitational collapse, and pre-Hawking radiation which is excited because of the time-dependent metric. We compare radiation emitted by a single collapsing shell with that emitted by two concentric shells of the equivalent total mass. We calculate the gravitational trajectory and the momentum energy tensor. We show that the flux of energy emitted during the collapse by a single shell is significantly different from the flux emitted by two concentric shells of the equivalent total mass. When the static black hole is formed, the fluxes become indistinguishable. This implies that an observer studying the flux of particles from a collapsing object could in principle reconstruct information not only about the total mass of the collapsing object, but also about the mass distribution.