This preprint, co-authored by Nobel Laureate Carl Wieman, looks at the difficulties that students had in understanding quantum tunneling.
Abstract: We report on a qualitative study of student learning of quantum tunneling in traditional and reformed modern physics courses. In the reformed courses, which were designed to address student difficulties found in previous research, students still struggle with many of the same issues found in other courses, but the reasons for these difficulties are more subtle, and many new issues are brought to the surface. By explicitly discussing how to build models of potential energy and relate these models to real physical systems, we have opened up a floodgate of deep and difficult questions as students struggle to make sense of these models. We conclude that the difficulties found in previous research are the tip of the iceberg, and the real issue at the heart of student difficulties in learning quantum tunneling is the struggle to build the complex models that are implicit in experts' understanding but often not discussed explicitly with students.
It's a lengthy paper, and I'm still reading it. But it is interesting that you get to learn quite a bit more about quantum tunneling in here, especially on aspects that are quite subtle.
Let me know what you think...