摘要
Ⅰ. INTRODUCTION Can black holes have 'hairs' other than the three well-known ones, i. e. the total mass, angular momentum and electric charges? This question has attracted much attention recently. Ref. [1] has pointed out that black holes can carry nonclassical discrete charges; Ref. [2] has studied the black holes with axion charges; Ref. [3] has discussed the existence of Skyrm charges on black holes; and Ref. [4] has investigated the problem whether black holes can carry QCD color charges.
基金
Project supported by the National Natural Science Foundation of China.
