Fig. 2

Dynamics of heat, correlations, and entropic quantities. a Internal energy of qubit A along the partial thermalization process. b Internal energy of qubit B. In the absence of initial correlations, the hot qubit A cools down and the cold qubit B heats up (cyan circles in panel a and b). By contrast, in the presence of initial quantum correlations, the heat current is reversed as the hot qubit A gains and the cold qubit B loses energy (orange squares in panel a and b). This reversal is made possible by a decrease of the mutual information c and of the geometric quantum discord d. Different entropic contributions to the heat current (5) in the uncorrelated e and uncorrelated f case. Reversal occurs when the negative variation of the mutual information, ΔI(A:B), compensates the positive entropy productions, \(S\left( {\rho _{\mathrm{A}}^\tau \parallel \rho _{\mathrm{A}}} \right)\) and \(S\left( {\rho _{\mathrm{B}}^\tau \parallel \rho _{\mathrm{B}}} \right)\), of the respective qubits. The symbols represent experimental data and the dashed lines are numerical simulations. Error bars were estimated by a Monte Carlo sampling from the standard deviation of the measured data (Supplementary Information)