  A fundamental connection between thermodynamics and information theory arises
from the fact that correlations exhibit an inherent work value. For
noninteracting systems this translates to a work cost for establishing
correlations. Here we investigate the relationship between work and
correlations in the presence of interactions that cannot be controlled or
removed. For such naturally coupled systems, which are correlated even in
thermal equilibrium, we determine general strategies that can reduce the work
cost of correlations, and illustrate these for a selection of exemplary
physical systems.
