Description:

Title: Quantum--classical correspondence past Ehrenfest time

Abstract: How does classical dynamics emerge from quantum dynamics? For a closed system, Egorov's theorem tells us that the classical and quantum descriptions agree up to times on the order $t \sim \log \frac{1}{h}$, which is far too short to explain the persistence of classical behavior in the real world. Instead, we consider open systems that interact with an external environment. The quantum and classical evolutions are described by Lindblad and Fokker--Planck equations respectively, and we will discuss the correspondence between the two.