Entanglement prethermalization in the Tomonaga-Luttinger model

Prethermalization refers to the relaxation to a quasi-stationary state before reaching thermal equilibrium. Recently, it is found that not only local conserved quantities but also entanglement plays a key role in a special type of prethermalization, called entanglement prethermalization. Here, we show that in the Tomonaga-Luttinger model the entanglement prethermalization can also be explained by the conventional prethermalization of two independent subsystems without entanglement. Moreover, it is argued that prethermalization in the Tomonaga-Luttinger model is essentially different from entanglement prethermalization in the Lieb-Liniger model because of the different types of energy degeneracies.