Quantum meeting: Maxwells demon crosses the quantum-to-classical transition

Maxwells thought experiment, where a ``neat-fingered being'' uses information on microscopic degrees of freedom to seemingly overcome the second law of thermodynamics, has been extensively studied in classical stochastic systems and more recently also in the quantum domain. In this talk, I will present an implementation of Maxwell's demon that can operate in both the quantum as well as the classical domain. By crossing the quantum-to-classical transition, this demon sheds light on the role of quantum effects in energy-to-work conversion. The demon is based on a double quantum dot where the on-site energies of the dots are manipulated based on the information acquired in a continuous charge measurement. Coherent tunneling between the dots allows for the buildup of quantum coherence in the system. In addition to the well-known Zeno effect, which prevents tunneling under strong continuous measurements, we find a Zeno-like effect in the weak measurement regime, where measurement errors result in dephasing through a rapid and random change of the on-site energies. We anticipate the role of quantum effects to show similar manifestations in other quantum systems under measurement and feedback control.