Coherent energy transfer at the quantum scale plays an increasingly important role in emerging platforms such as quantum batteries and engineered many-body quantum systems. In this setting, ergotropy, the maximum work extractable from a quantum state via unitary operations, quantifies the operationally accessible energy stored in a quantum system. Standard formulations of ergotropy assume complete knowledge of the quantum state, enabling the construction of a globally optimal unitary transformation.

In realistic experimental scenarios, however, the knowledge of the system is typically restricted to a limited set of observables. Such observational constraints fundamentally limit the information available about the state and therefore the amount of extractable work. This raises the following questions: Can one design an ergotropy extraction protocol that operates under restricted measurement access? And can such a protocol be realized on an existing experimental platform? In this talk, we explore an observational ergotropy extraction protocol introduced in [1] and analyze the feasibility of its implementation within a trapped-ion quantum simulator architecture.

[1]  Šafránek, D., Rosa, D., & Binder, F.,  Physical Review Letters 130, 210401 (2023).