Experimental Demonstration of Correlation-Assisted Energy Extraction Gain

Within the framework of microscopic thermodynamics, correlations can play a crucial role in energy extraction. We experimentally investigated the link between information encoded in tunable correlations and its utility for feedback-assisted energy transfer. We realized an agent-demon protocol involving two trapped-ion qubits and show that an appropriate feedback policy increases the average energy stored in the demon qubit by capitalizing on correlations between the constituents. For the chosen family of nearly pure resource states, we quantify both the concurrence and the feedback-assisted energy gain and observe the predicted relation between them. We also show theoretically that the same fixed protocol yields the same gain after complete dephasing in the local energy basis. The experiment establishes a concurrence–gain relation within the investigated pure-state family.