  Of indisputable relevance for non-equilibrium thermodynamics, fluctuations
theorems have been generalized to the framework of quantum thermodynamics, with
the notion of work playing a key role in such contexts. The typical approach
consists of treating work as a stochastic variable and the acting system as an
eminently classical device with a deterministic dynamics. Inspired by
technological advances in the field of quantum machines, here we look for
corrections to work fluctuations theorems when the acting system is allowed to
enter the quantum domain. This entails including the acting system in the
dynamics and letting it share a nonclassical state with the system acted upon.
Moreover, favoring a mechanical perspective to this program, we employ a
concept of work observable. For simplicity, we choose as theoretical platform
the autonomous dynamics of a two-particle system with an elastic coupling. For
some specific processes, we derive several fluctuation theorems within both the
quantum and classical statistical arenas. In the quantum results, we find that,
along with entanglement and quantum coherence, aspects of inertia also play a
significant role since they regulate the route to mechanical equilibrium.
