Ghost condensate and generalized second law
  Dubovsky and Sibiryakov recently proposed a scenario in which particles of
different species propagate with different speeds due to their direct couplings
to ghost condensate. It was argued that this extended version of ghost
condensate allows a gedanken experiment leading to violation of the generalized
second law. However, in the original ghost condensate scenario, difference in
propagation speeds is suppressed by M^2/M_{Pl}^2, where M is the order
parameter of spontaneous Lorentz breaking and M_{Pl} is the Planck scale. In
this case the energy transfer necessary for the gedanken experiment is so slow
that the timescale of decrease of entropy, if any, is always longer than the
Jeans timescale of ghost condensate. Hence the generalized second law is not
violated by the gedanken experiment in the original ghost condensate scenario.
This conclusion trivially extends to gauged ghost condensation by taking into
account accretion of gauged ghost condensate into a black hole.
