The Fixed-q Edge Limit of the q-Krawtchouk Ensemble
Abstract
We study the fixed-q right-edge asymptotics of the ordinary q-Krawtchouk ensemble. For 0<q<1, finite polynomial duality gives a direct proof of convergence of the correlation kernels to an explicit limiting kernel. The local Jacobi limit is a shifted continuous q−1-Hermite expression with an indeterminate moment problem, so the limiting Jacobi expression does not determine a unique self-adjoint operator. A single spectral atom, asymptotically saturating the mass bound, selects the realization and yields strong-resolvent convergence. The limiting kernel represents its positive spectral projection and admits spectral-series, Christoffel--Darboux, and partial-theta representations. After a ground-state transformation, the associated dual operator agrees with a two-step spatial Markov operator of Borodin--Corwin. For q>1, the limiting Jacobi operator is of Al-Salam--Carlitz~I type and is essentially self-adjoint.
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BibTeX
@misc{nikitin2026fixedq,
title = {{The Fixed-$q$ Edge Limit of the $q$-Krawtchouk Ensemble}},
author = {Pavel Nikitin},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.24149},
eprint = {2609.24149},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.24149},
}
RIS
TY - UNPB
TI - The Fixed-q Edge Limit of the q-Krawtchouk Ensemble
AU - Pavel Nikitin
PY - 2026
DA - 2026/10/23
PB - arXiv
DO - 10.48550/arxiv.2609.24149
UR - https://arxiv.org/abs/2609.24149
AB - We study the fixed-q right-edge asymptotics of the ordinary q-Krawtchouk ensemble. For 0<q<1, finite polynomial duality gives a direct proof of convergence of the correlation kernels to an explicit limiting kernel. The local Jacobi limit is a shifted continuous q^−1-Hermite expression with an indeterminate moment problem, so the limiting Jacobi expression does not determine a unique self-adjoint operator. A single spectral atom, asymptotically saturating the mass bound, selects the realization and yields strong-resolvent convergence. The limiting kernel represents its positive spectral projection and admits spectral-series, Christoffel--Darboux, and partial-theta representations. After a ground-state transformation, the associated dual operator agrees with a two-step spatial Markov operator of Borodin--Corwin. For q>1, the limiting Jacobi operator is of Al-Salam--Carlitz~I type and is essentially self-adjoint.
ER -