Multipoint distributions of the KPZ fixed point with compactly supported initial conditions

Fuente: arXiv
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Main Authors: Liao, Yuchen, Liu, Zhipeng
Format: Preprint
Published: 2025
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_version_ 1866914060497321984
author Liao, Yuchen
Liu, Zhipeng
author_facet Liao, Yuchen
Liu, Zhipeng
contents The KPZ fixed point is a universal limiting space-time random field for the Kardar-Parisi-Zhang universality class. While the joint law of the KPZ fixed point at a fixed time has been studied extensively, the multipoint distributions of the KPZ fixed point in the general space-time plane are much less well understood. More explicitly, formulas were only available for the narrow wedge initial condition arXiv:1906.01053, arXiv:1907.09876 and the flat initial condition arXiv:1907.09876 for the multipoint distributions, and the half-Brownian and Brownian initial conditions arXiv:2010.07357v1, arXiv:2504.19975 for the two-point distributions. In this paper, we obtain the first formula for the space-time joint distributions of the KPZ fixed point with general initial conditions of compact support. The formula is obtained through taking $1:2:3$ KPZ scaling limit of the multipoint distribution formulas for the totally asymmetric simple exclusion process (TASEP). A key ingredient is a probabilistic representation, inspired by arXiv:1701.00018, of the kernel encoding the initial condition for TASEP, which was first defined through an implicit characterization in arXiv:1907.09876. Moreover, we also verify that the equal time version of our formula matches the path integral formula in arXiv:1701.00018 for the KPZ fixed point when the initial condition is of compact support.
format Preprint
id arxiv_https___arxiv_org_abs_2509_03246
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Multipoint distributions of the KPZ fixed point with compactly supported initial conditions
Liao, Yuchen
Liu, Zhipeng
Probability
Mathematical Physics
60K35 (Primary), 60G60 (Secondary)
The KPZ fixed point is a universal limiting space-time random field for the Kardar-Parisi-Zhang universality class. While the joint law of the KPZ fixed point at a fixed time has been studied extensively, the multipoint distributions of the KPZ fixed point in the general space-time plane are much less well understood. More explicitly, formulas were only available for the narrow wedge initial condition arXiv:1906.01053, arXiv:1907.09876 and the flat initial condition arXiv:1907.09876 for the multipoint distributions, and the half-Brownian and Brownian initial conditions arXiv:2010.07357v1, arXiv:2504.19975 for the two-point distributions. In this paper, we obtain the first formula for the space-time joint distributions of the KPZ fixed point with general initial conditions of compact support. The formula is obtained through taking $1:2:3$ KPZ scaling limit of the multipoint distribution formulas for the totally asymmetric simple exclusion process (TASEP). A key ingredient is a probabilistic representation, inspired by arXiv:1701.00018, of the kernel encoding the initial condition for TASEP, which was first defined through an implicit characterization in arXiv:1907.09876. Moreover, we also verify that the equal time version of our formula matches the path integral formula in arXiv:1701.00018 for the KPZ fixed point when the initial condition is of compact support.
title Multipoint distributions of the KPZ fixed point with compactly supported initial conditions
topic Probability
Mathematical Physics
60K35 (Primary), 60G60 (Secondary)
url https://arxiv.org/abs/2509.03246