KPZ equation from open ASEP with general boundary asymmetry

Abstract: We consider generalizations of open ASEP in the interval and half-space, where the speed of the reservoir dynamics can depend on the local particle configuration. We show that their height functions have a continuum limit given by the open KPZ equation. This removes the assumption of Liggett's condition in Corwin-Shen '18 and Parekh '19, thus answering a question of Corwin, and it also removes the assumption of product invariant measures in Goncalves-Perkowski-Simon '20.