Lifting curves simply

Abstract

We provide linear lower bounds for $f_\rho(L)$, the smallest integer so that every curve on a fixed hyperbolic surface $(S,\rho)$ of length at most $L$ lifts to a simple curve on a cover of degree at most $f_\rho(L)$. This bound is independent of hyperbolic structure $\rho$, and improves on a recent bound of Gupta-Kapovich. When $(S,\rho)$ is without punctures, using work of Patel we conclude asymptotically linear growth of $f_\rho$. When $(S,\rho)$ has a puncture, we obtain exponential lower bounds for $f_\rho$.