The Gibbs paradox, the Landauer principle and the irreversibility
  associated with tilted observers
  It is well known that, in the context of General Relativity, some spacetimes,
when described by a congruence of comoving observers, may consist in a
distribution of a perfect (non-dissipative) fluid, whereas the same spacetime
as seen by a "tilted"' (Lorentz-boosted) congruence of observers, may exhibit
the presence of dissipative processes. As we shall see, the appearence of
entropy producing processes are related to the tight dependence of entropy on
the specific congruence of observers. This fact is well illustrated by the
Gibbs paradox. The appearance of such dissipative processes, as required by the
Landauer principle, are necessary, in order to erase the different amount of
information stored by comoving observers, with respect to tilted ones.
