On A Relation Between $q$-Exponential And $\theta$-Function
  We will use a discrete analogue of the classical Laplace method to show that for infinitely many positive integers $n$, the main term of the asymptotic expansion of the scaled $q$-exponential $(-q^{-nt+1/2}u;q)_{\infty}$ could be expressed in $\theta$-function. 
Ruiming Zhang