# WKB asymptotics of meromorphic solutions of difference equations

## TL;DR

This paper investigates the asymptotic behavior of meromorphic solutions to a difference Schrödinger equation with a pole in the potential, extending WKB methods to complex difference equations with singularities.

## Contribution

It develops a WKB asymptotic analysis for meromorphic solutions of difference equations with poles, generalizing classical semi-classical methods to complex difference operators.

## Key findings

- Derived asymptotic formulas for solutions near poles
- Extended WKB techniques to meromorphic potentials
- Analyzed the behavior of solutions in complex domains

## Abstract

We consider the difference Schr{\''o}dinger equation $\psi(z+h)+\psi(z-h)+ v(z)\psi(z)=0$ where $z$ is a complex variable and $h$ is a small positive parameter. If $v$ is an analytic function, then, for $h$ sufficiently small, the analytic solutions to this equation have standard semi-classical behavior that can be described by means of an analog of the complex WKB method for differential equations. In the present paper, we assume that $v$ has a simple pole and, in its neighborhood, we study the asymptotics of meromorphic solutions to the difference Schr{\''o}dinger equation.