1. quantum thermometers, quantum batteries, and lesser demons

Stefan Nimmrichter

University of Siegen, Germany

25 August 2022 Thu 4 pm

                                      IBS Center for Theoretical Physics of Complex Systems (PCS), Administrative Office (B349), Theory Wing, 3rd floor

                                      Expo-ro 55, Yuseong-gu, Daejeon, South Korea, 34126 Tel: +82-42-878-8633                     

Quantum thermodynamics bridges the gap between statistical physics and quantum information theory, reformulating the laws of thermodynamics for small open quantum systems under external control and leading to quantum-enhanced thermal devices. For example, a quantum thermometer that infers the temperature of a thermal reservoir by locally probing it through collisions with a fast sequence of qubits can achieve higher accuracy than a conventional equilibrium thermometer. Quantum coherence can also result in improved performance of thermodynamic protocols extracting useful work from thermal resources. When storing work in a quantum battery, for instance, we can gain an advantage in the battery charging time if the work is stored in a quantum-coherent form. Finally, quantum measurement-feedback channels can be used to design so-called Maxwell demon engines that extract work from heat via continuous observation of the working medium, e.g., with help of a pointer degree of freedom. Such a scheme alleviates Maxwell's demon paradox and incorporates Landauer's erasure principle in a self-contained model that can operate in temperature regimes where simple quantum Otto engines would fail.