LECTURES ON BLACK-HOLES AND INFORMATION LOSS

In these lectures, the author's point of view on the problem of Hawkin g Evaporation of Black Holes is explained in some detail. A possible r esolution of the information loss paradox is proposed, which is fully in accord with the rules of quantum mechanics. Black hole formation an d evaporation leaves over a remnant which looks pointlike to an extern al observer with low resolving power, but actually contains a new infi nite asymptotic region of space. Information can be lost to this new r egion without violating the rules of quantum mechanics. However, the t hermodynamic nature of black holes can only be understood by studying the results of measurements that probe extremely small (sub-Planck sca le) distances and times near the horizon. Susskind's description of th ese measurements in terms of string theory may provide an understandin g of the Bekenstein-Hawking (BH) entropy in terms of the states of str anded strings that cross the horizon. The extreme nonlocality of strin g theory when viewed at short time scales allows one to evade all caus ality arguments which pretend to prove that the information encoded in the BH entropy can only be accessed by the external observer in times much longer than the black hole evaporation time. The present author believes however that the information lost in black hole evaporation i s generically larger than the BH entropy, and that the remaining infor mation is causally separated from the external world in the expanding horn of a black hole remnant or cornucopion. The possible observationa l signatures of such cornucopions are briefly discussed.