Rational curves on Calabi-Yau threefolds and a conjecture of Oguiso

This short note is an extended abstract of a talk given at the conference “Komplexe Analysis” at the Mathematisches Forschungsinstitut Oberwolfach in September 2012. We explained some recent results about the existence of rational curves on Calabi-Yau threefolds as well as a curvature approach to the non hyperbolicity of such manifolds.