Asymptotic behavior for twisted traces of self-dual and conjugate self-dual representations of $\mathrm{GL}_n$
Yugo Takanashi, Satoshi Wakatsuki
TL;DR
This work advances the twisted limit multiplicity program for GL_n by analyzing the level-aspect asymptotics of twisted traces for self-dual and conjugate self-dual representations. It employs the Arthur twisted invariant trace formula to isolate main terms, and develops a comprehensive Fourier-analytic framework for twisted orbital integrals, linking them to endoscopic lifts from classical groups. The authors establish explicit asymptotic formulas and automorphic density results in the twisted setting, with globalization applications for constructing self-dual and conjugate self-dual automorphic representations. By exploiting local and global Langlands correspondences and endoscopic transfer, the paper connects geometric orbital data with spectral Plancherel measures, providing concrete measures for twisted endoscopic groups and advancing density theorems for conjugate self-dual GL_n representations. The results have potential impact on automorphic representation counting, globalization strategies, and endoscopy-driven understandings of the automorphic spectrum in the twisted context.
Abstract
In this paper, we study the asymptotic behavior of the sum of twisted traces of self-dual or conjugate self-dual discrete automorphic representations of $\mathrm{GL}_n$ for the level aspect of principal congruence subgroups under some conditions. Our asymptotic formula is derived from the Arthur twisted trace formula, and it is regarded as a twisted version of limit multiplicity formula on Lie groups. We determine the main terms for the asymptotic behavior under different conditions, and also obtain explicit forms of their Fourier transforms, which correspond to endoscopic lifts from classical groups. Its main application is the self-dual (resp. conjugate self-dual) globalization of local self-dual (resp. conjugate self-dual) representations of $\mathrm{GL}_n$. We further derive an automorphic density theorem for conjugate self-dual representations of $\mathrm{GL}_n$.
