Convergence of the open WASEP stationary measure without Liggett's condition
Zoe Himwich
TL;DR
The paper demonstrates that Liggett's condition is unnecessary for the convergence of open ASEP stationary measures to the open KPZ stationary measure under weak asymmetry scaling. By analyzing the Askey–Wilson process and its tangent limit, the authors show convergence to the continuous dual Hahn process, yielding the open KPZ stationary law in the limit, with the limit independent of certain boundary parameters. A Laplace-transform framework links finite-N AW representations to the CDH limit, and a coupling-based tightness argument establishes process-level convergence for the stationary height function. This work broadens the parameter regime for KPZ universality in open systems and supports conjectures about broader convergence beyond Liggett’s condition.
Abstract
We demonstrate that Liggett's condition can be relaxed without disrupting the convergence of open ASEP stationary measures to the open KPZ stationary measure. This is equivalent to demonstrating that, under weak asymmetry scaling and appropriate scaling of time and space, the four-parameter Askey-Wilson process converges to a two-parameter continuous dual Hahn process. We conjecture that the convergence of the open ASEP height function process to solutions to the open KPZ equation will hold for a wider range of ASEP parameters than those permitted by Liggett's condition.
