Confinement and lack of thermalization after quenches in the bosonic Schwinger model

TL;DR

This study investigates the out-of-equilibrium dynamics of the bosonic Schwinger model, revealing confinement effects, lack of thermalization, and the emergence of exotic states with distinct entanglement properties.

Contribution

It demonstrates confinement and non-thermalization in the bosonic Schwinger model after quenches, highlighting the formation of unique asymptotic states.

Findings

Bosons exhibit confinement evidenced by light cone bending.

System evades thermalization within simulated time scales.

Asymptotic states feature a deconfined region and an area-law entanglement core.

Abstract

We excite the vacuum of a relativistic theory of bosons coupled to a $U(1)$ gauge field in 1+1 dimensions (bosonic Schwinger model) out of equilibrium by creating a spatially separated particle-antiparticle pair connected by a string of electric field. During the evolution, we observe a strong confinement of bosons witnessed by the bending of their light cone, reminiscent of what has been observed for the Ising model [Nat. Phys. 13, 246 (2017)]. As a consequence, for the time scales we are able to simulate, the system evades thermalization and generates exotic asymptotic states. These states are made of two disjoint regions, an external deconfined region that seems to thermalize, and an inner core that reveals an area-law saturation of the entanglement entropy.