Heat flow can act as a witness to a system’s quantum properties
Alexssandre de Oliveira Junior and Jonatan Bohr Brask of the Technical University of Denmark, with Patryk Lipka-Bartosik of Jagiellonian University, proved that quantum features of a system leave a measurable signature in the heat it exchanges with its surroundings.
Drawing on the logic of Maxwell's demon, they showed that a quantum memory reshapes heat-flow patterns between a system and a thermal bath in ways that can only arise when coherence or entanglement is present. This lets experimenters certify quantum properties indirectly — by thermometry on the environment rather than fragile direct measurement of the system.
The result tightens the link between information-theoretic resources and thermodynamic observables, a central theme in the physics of information.