关联与黑洞信息丢失问题

Correlation and the black hole information loss problem

霍金计算发现黑洞会发出热辐射.由于热辐射之间不存在关联,因此辐射粒子无法将信息携带出黑洞,伴随着霍金辐射,黑洞内部的物质信息逐渐丢失.量子力学幺正性要求信息守恒,黑洞信息丢失与量子力学幺正性存在明确的冲突,此即黑洞信息丢失之谜.霍金辐射之间是否存在关联是解决黑洞信息丢失问题的关键.霍金最初的计算中没有考虑辐射粒子的反冲,得到的辐射谱为纯热谱.后来, Parikh和Wilczek的计算表明,如果计入辐射粒子的反冲,则辐射谱可能会轻微地偏离热谱.本文首先介绍了Parikh和Wilczek使用包含辐射粒子反冲的量子隧穿方法得到的非热谱.其次,介绍了张保成等人在非热谱基础上证明黑洞辐射粒子之间存在关联,并且黑洞辐射过程信息守恒的工作.最后,介绍了黑洞辐射之间如何产生关联的一种可能的物理机制,黑洞辐射粒子之间的引力关联可以携带信息,使得黑洞辐射过程中信息守恒.

Information is physical, it cannot simply disappear in any physical process. This basic principle of information science constitutes one of the most important elements for the very foundation to our daily life and to our understanding of the universe. However, this ftmdamental principle is challenged by the physics of black holes. Classic black holes was viewed as only capable of absorbing but not emitting particles, so black holes look completely black. All matter that ＂falls into the black hole will be stored in the black hole forever, and the information carry by these matter will always be stored in the black hole. Although the information in the black hole cannot be seen, we know that the information has not been lost. After considering the quantum effect, the black hole is no longer completely black. By considering quantum effect of black hole, Hawking shows that black holes emit thermal radiation like ordinary hot bodies. It is well known that there is no correlation between thermal radiation, therefore no information can be carried out by Hawking radiation. With the black hole evaporating, the information inside the black hole will gradually be lost. However, the unitary property of quantum mechanics indicates that information is conserved, therefore, the loss of black hole information conflicts with the unitary of quantum mechanics, this is the so-called mystery of black hole information loss. This problem reflects the conflict between gravitational theory and quantum theory, and attracts wide attention of scientists. Whether there is a correlation between Hawking radiation is the key to solving the problem of black hole information loss. Without considering the self-gravitating of the radiating particles in Hawking＇s initial calculations, he obtained the results of the pure thermal spectrum, so his result is inconsistent with energy conservation. Kraus and Wilczek show that the thermal spectrum may be corrected if the self-gravitating of the radiant particles is taken into account, thus Hawking radiations must be correlated, and their correlations can carry away information encoded within. This paper firstly introduced the black hole radiation non-thermal spectrum obtained by Parikh and Wilczek, who use the method of quantum tunneling after counting the self-gravitating of radiation particles; then it also introduced the research of Zhang et al., which proves that the entropy is conservation during black hole radiation process based on the non-thermal spectrum obtained by Parikh and Wilczek; and finally we proposed a possible physical mechanism for the correlation between black hole radiation, which shows that the gravitational correlation between the black hole radiation particles can carry information, so that the information is conserved during the black hole radiation process. The series of research on black hole information loss problem reveals that information conservation remains true when gravitational correlations among Hawking radiations are properly taken into account. Information conservation principle thus states Hawking radiation is unitary, which shows that the dynamics of a black hole obey the laws of quantum mechanics. Since a black hole is a result of general relativity, the unitarity of a black hole definitely indicates the possibility of a unified gravity and quantum mechanics.