Author(s): Qing-Feng Xue, Qi Zhang, Xu-Cai Zhuang, Ying-Jie Zhang, Yun-Jie Xia, Enrico Russo, Giulio Chiribella, Rosario Lo Franco, and Zhong-Xiao Man The principle that heat spontaneously flows from higher temperatures to lower temperatures is a cornerstone of classical thermodynamics. While this principle holds true for macroscopic systems at equilibrium, here we show that, when a quantum system undergoes two thermalization processes in an indef… [Phys. Rev. Lett. 137, 030404] Published Tue Jul 14, 2026