1. nonequilibrium entropy and the second law in quantum many0body systems

Philipp Strasberg

Universitat Autònoma de Barcelona, Spain

14 September 2021 Tue 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                     

This is an introductory talk about the second law of thermodynamics and the associated problem of finding meaningful notions of thermodynamic entropy, heat and temperature (all supposed to be valid out of equilibrium). The problem is mostly viewed from the perspective of quantum many-body systems, ultracold atoms and open quantum systems and the talk starts by reviewing the second law and entropy concept from a phenomenological and historical perspective. Afterwards, three different candidates to define thermodynamic entropy are discussed: the familiar von Neumann and Boltzmann entropies and the (not so familiar) observational entropy (albeit the latter was explicitly proposed by von Neumann as the correct entropy concept in statistical mechanics). Based on this last entropy candidate, and together with microscopic definitions of heat and temperature, the talk finishes by explaining how the second law can be derived and quantified in isolated and open quantum systems.