Entanglement prethermalization: Locally thermal but non-locally non-thermal states in a one-dimensional Bose gas

Understand

A well-isolated system often shows relaxation to a quasi-stationary state before reaching thermal equilibrium.

• Such a prethermalization has attracted considerable interest recently in association with closely related fundamental problems of relaxation and thermalization of isolated quantum systems.
• Motivated by the recent experiment in ultracold atoms, we study the dynamics of a one-dimensional Bose gas which is split into two subsystems, and find that individual subsystems relax to Gibbs states, yet the entire system does not due to quantum entanglement.
• In view of recent experimental realization on a small well-defined number of ultracold atoms, our prediction based on exact few-body calculations is amenable to experimental test.