Periodic $q$-Whittaker and Hall-Littlewood processes

TL;DR

This paper investigates the properties of periodic $q$-Whittaker and Hall-Littlewood processes, revealing symmetries, integral formulas, and connections to vertex models, thereby extending previous results in integrable probability.

Contribution

It introduces a $(q,u)$ symmetry for the periodic $q$-Whittaker process, provides contour integral formulas, and links these processes to stochastic six vertex models.

Findings

Established a $(q,u)$ symmetry after a random shift.

Derived contour integral formulas for the processes.

Connected observables to the stochastic six vertex model.

Abstract

We study the periodic $q$-Whittaker and Hall-Littlewood processes, two probability measures on sequences of partitions. We prove that a certain observable of the periodic $q$-Whittaker process exhibits a $(q,u)$ symmetry after a random shift, generalizing a previous result of Imamura, Mucciconi, and Sasamoto who showed a matching between the periodic Schur and $q$-Whittaker measures, and also give a vertex model formulation of their result. As part of our proof of the $(q,u)$ symmetry, we obtain contour integral formulas for both the periodic $q$-Whittaker and Hall-Littlewood processes. We also show a matching between certain observables in the periodic Hall-Littlewood process and in a quasi-periodic stochastic six vertex model after a suitable random shift, and discuss a limit to the stationary periodic stochastic six vertex model.