Virtual Black Holes at Linear Colliders
  We propose that future linear colliders can create virtual black holes even though their energies are below the fundamental scale, because of the uncertainty principle. These virtual black holes provide us much information which cannot be obtained in the production of black holes at the LHC or other hadron colliders. We can observe lepton flavor and lepton (baryon) number violating processes at linear colliders by using virtual black holes. And virtual black holes can be used to the precision measurements of top and W. They can create only one top quark or one W boson, which leads to the clean signal that cannot be obtained in pair-production processes. 
Yosuke Uehara