Near-frozen high energy state in a chiral channel driven out of equilibrium

Ergodic many-body systems are expected to reach quasi-thermal equilibrium. Here we demonstrate that, surprisingly, high-energy electrons, which are injected into an interacting one-dimensional quantum Hall edge mode, stabilize at a far-from-thermalized state over a long-time scale. To detect this non-equilibrium state, one positions an energy-resolved detector downstream of the point of injection. Previous works have shown that electron distributions, which undergo short-ranged interactions, generically relax to near-thermal asymptotic states. Here, we consider screened interactions of finite range. The thus-obtained many-body state comprises fast-decaying transient components, followed by a nearly frozen distribution with a peak near the injection energy.