Work extraction under incomplete state knowledge and measurement-based feedback

Determine how the work-extraction bounds for isolated quantum many-body systems across thermodynamic levels are modified when control operations must be selected without complete knowledge of the initial state and when measurements and measurement-based feedback are incorporated.

Background

The framework assumes that the initial quantum state is fixed and fully known to the operator, who can optimize the operation for that state. The entropy difference between restricted and enlarged thermodynamic levels therefore represents information that is inaccessible to the allowed operations, rather than information unknown to the operator.

The authors explicitly identify as unresolved the effect of incomplete state knowledge on the bounds, including uncertainty caused by imperfect state preparation, and also ask how the bounds change when measurement and measurement-based feedback are permitted. Addressing this problem would extend the framework from state-tailored protocols to protocols designed under uncertainty about the initial state.