Singular Gauss sums, Polya-Vinogradov inequality for $GL(2)$ and growth of primitive elements

We establish an analogue of the classical Polya-Vinogradov inequality for $GL(2, F_p)$, where $p$ is a prime. In the process, we compute the `singular Gauss sums for $GL(2, F_p)$. As an application, we show that the collection of elements in $GL(2,Z)$ whose reduction modulo $p$ are of maximal order in $GL(2, F_p)$ and whose matrix entries are bounded by $x$ has the expected size as soon as $xgg p^{1/2+ep}$ for any $ep>0$. In particular, there exist elements in $GL(2,Z)$ with matrix entries that are of the order $O(p^{1/2+ep})$ whose reduction modulo $p$ are primitive elements.