  We study the boundary CFT under supertranslation in terms of the AdS/CFT
correspondence. In particular, we probe the soft hair BTZ background by several
open string configurations as follows. The Ryu-Takayanaki formula of
holographic entanglement remains intact under supertranslation. The U-shape
string probe indicates that the flat part of meson potential is altered by the
soft charge. The trailing string solution shows that the hair parameter plays
the role of external field in the drag force. The study of hanging string in
the Brownian motion suggests the transport variables, such as friction
coefficient are likely affected by supertranslation.
