  We review black holes with second-order phase transition in string theory
(R-charged black holes and holographic superconductors) and review their static
and dynamic critical phenomena. Holographic superconductors have conventional
mean-field values for static critical exponents, but R-charged black holes have
unconventional ones. For dynamic universality class, holographic
superconductors belong to model A, and R-charged black holes belong to model B
in the classification of Hohenberg and Halperin. The analysis suggests that
some black holes do obey the theory of critical phenomena in condensed matter
physics.
