Speaker: Takahiro Sagawa The University of Tokyo
Time: 2021-10-27 19:00-2021-10-27 20:00
Venue: MMW S727 + Skype: https://join.skype.com/xuyg31CGkgoj

Abstract:

In equilibrium thermodynamics, the Boltzmann entropy serves as a complete thermodynamic potential that characterizes state convertibility in a necessary and sufficient manner. In this talk, I will present our result [1,2] that a complete thermodynamic potential emerges for quantum many-body systems under physically reasonable assumptions, even in out-of-equilibrium and fully quantum situations. Our proof is based on the resource-theoretic formalism of thermodynamics and the quantum ergodic theorem. The complete thermodynamic potential is in general given by a quantity called the spectral divergence rate, while under some assumptions it reduces to the Kullback-Leibler (KL) divergence rate. In addition, I will discuss the case where an auxiliary system called a catalyst is introduced, and show that the KL divergence again serves as a complete thermodynamic potential if a small amount of correlation is allowed between the system and the catalyst [3].

Short Bio:

Prof. Takahiro Sagawa is a professor at the Department of Applied Physics, School of Engineering, The University of Tokyo. He is a theoretical physicist working on nonequilibrium statistical mechanics (especially in small fluctuating systems), quantum measurement, control, and information theory (in open systems).

References:

[1] P. Faist, T. Sagawa, K. Kato, H. Nagaoka, F. Brandao, Phys. Rev. Lett. 123, 250601 (2019).

[2] T. Sagawa, P. Faist, K. Kato, K. Matsumoto, H. Nagaoka, F. Brandao, arXiv:1907.05650

[3] N. Shiraishi, T. Sagawa, Phys. Rev. Lett. 126, 150502 (2021).